Hello everyone ... I am new here so thanks for the add. I am looking at buying a mid 1970's model cat 988B. It has been used as a dam building desilting machine for the last decade. Before that it was in a quarry. About 8 years ago It had the touque converter pulled out and re-sealed .... since then it has de-silted around 40 smaller dams ( around 20 hours each ) on Australian cattle stations. ( ranches ) The machine ran very well during this time. It was then was parked up & sat for around 9 months. Since being activated again it straight away developed a water heating issue. It will heat up quickly when digging ( under load ) but will cool again quiet quickly when it is at a high idle for a few minutes. What are your thoughts ?
get a non contact thermometer and see what the temp is of the coolant outlet on the engine to the radiator, and the inlet back from the radiator, while the engine is overheated. So the temp of the coolant leaving the engine and coming back to the engine, but read a cast iron surface with paint on it hopefully. Or the radiator as long as you're not reading bare metal, (different emmisivity). Could be simple, plugged radiator internally with rust and lime, externally with chaff and dust, loose belt, water pump impeller gone, thermostat shot, the temps will point you in the right direction. Is this based on the coolant temp gauge? or is it blowing off steam? bubbling? Just the coolant, or anything else overheating?
It gets hot on the guage and bubbles off steam from the radiator filler if you let it get that hot. The Belts are tight and radiator fins are nice and clean ( can see right through radiator easily ) It only started getting got hot after sitting for 9 months. And only gets hot under load ( digging / working hard ) It will cool quickly if let idle.
Delmer gives many good ideas. Just for fun I'm attaching the troubleshooting list from Cat: Some of what is mentioned would not apply to a 988B. Also found a test for water pump pressure, never tried this one but would think it would be done with filler cap off or at least cold coolant or you could be seeing pressure not from pump flow.
Thanks.... will look into it more. As I have not a lot of experienced with this machine, I have another question. It has a driveline ' thump ' when engaging from reverse to foward and foward to reverse. Is this normal for a machine of that vintage ? It has around 19,000 hrs and the serial number is 50W 38 44.
Hard to diagnose a "thump" via text message. But there would be some feel or sound when the normal slack in drive line is taken up. I would want to have someone shifting it between gears with foot brakes applied while I watched and listened to see where it was coming from. And make sure if you do this to have someone you really trust in the drivers seat so as to not get run over! Could be normal but also could be bad u-joints, center bearing, transmission mounts and so on. Also could be more noticeable if the engine RPMs too high. Might also want to try shifting with parking brake applied to see if that changes things.
Another thing to check is torque converter outlet temperature which can drive up engine coolant temperature. I mention this because you mention the speed with which the radiator heats and cools. The other issue of thumps when shifting into and out of gear involves loose rear axle trunnions. You will see the whole axle tilt when shifting into reverse.
Delmer's suggestion of a non-contact thermometer is one that you should pursue first. Shoot some temperatures of the coolant hoses as a first step. Then as John pointed out, keep an eye on the torque converter outlet temperature while the machine is working. It may be that increased heat from the power train is causing the coolant to heat up and that's why the coolant temp falls like a stone when you run the engine at High Idle in neutral with the machine stationary. Please give an indication of how long (in seconds/minutes) the coolant temp takes to drop to a "normal" range. I think the concentration should be on fixing the temperature issue first and address the "clunk" later, but I will ask one question. Is the operator using the left pedal while making F->N->R direction changes.?
I started the machine to charge the batteries as it has been sitting now for a while. ( couldnt drive it as it is the monsoon wet season here and the soil is too boggy ) Since it wasnt under any load while the engine was running I couldnt get it hot and only just got it to the normal operating temp on the guage. After 15-20 mins of idle and revving, the two pipes from the top of radiator to the engine heads were very hot to touch but the coolant in the radiator was only just barely warm when I put my finger in. At the same time, the larger pipe from the engine to the bottom of radiator was cold to touch. How many thermostats does that v8 engine have and where are they located.
If you want to get the temps up without moving it put it in 3rd gear and with one foot on the right brake pedal press the throttle with the other and run it at converter stall for a couple of minutes until the converter out temperature alarm goes off. At that point keep the engine at high idle and shift to neutral until the converter temp goes down, then repeat until the coolant temp gets to the top end of the normal range. You have to remember that the coolant temp sender that gives the signal to the gauge is in the cylinder head, not in the radiator. There are two thermostats, reference #8 in the illustration below. Part Number is 9N-2894. You'll also need two gaskets 4N-1156 because they are guaranteed to break when you pull the covers off. I'm not sure that thermostats are your problem though, but if you want to go that route don't let fear stop you. A couple more questions - What servicing has been done to this loader after sitting for so long before putting it to work.? What type of coolant is in the radiator..?
Thanks for the tip Nige. Cant see your illustration...... The loader had no new oils after sitting as the oils were recently seviced before sitting. The radiator was flushed after the heating problem started and as the owner didnt have enough coolant ( and lives 180 miles from the nearest town ) he filled it with clean water just to see if the problem changed. It is still filled with water at the moment. He was enlarging a dam for me at the time & run the machine slower than usual to keep the temps down. He finished the job and other than a few small jobs ( less than 1 hr each ) the machine has been more or less sitting again. The transmission oil smells and looks very clean and brand new on the dip stick. To answer your question about the ' thud ' : it seems to do it whith and without left pedal use. The noise cant be heard while standing beside the machine, but can be felt/heard from inside the cab. (It is not a ' metal breaking, bang ' sound but rather a ' heavy dull thump ' & seems to come from down in the centre/rear area of the machine ) The owner says its normal and has always done it since he owned it. ( about 10 years )
Another option I thought of was is it possible that a previous owner has opened the fuel rack in the fuel pump thus causing an overfueling issue under load ? I ask this because there seems to be a lot of contiuous black smoke coming out of her when under load ( digging, reversing out of the hole ect... ) and a slight smoke that stings your eyes when at idle.
Apologies. Here is the illustration. I forgot to attach it above.
Have you tried running it without the air filters, just as a test.?
Yes need to be sure the engine can get the air it needs! Been many years since I touched one of those but if running right should have very minimal smoke except maybe when first stomping on the throttle. Might also want to check to see if there is a problem with exhaust system. Either plugged muffler or leaking between the heads and the plumbing to the turbo.
Thanks .... will try the suggestions. The air cleaner elements look like new ( very clean ). The exhaust seems to breath easy enough but has a leaking join between the turbo and exhaust baffle. ( Bit of black soot coming from the join ) Question : if it was the touque converter, wouldnt the coolant temps be inclined to stay high rather than cool rapidly at high idle ?
Pull them out and run the test anyway. Fix it before proceding further. It may also be worth pulling off the intake hose and check the turbo for bearing play while you're at it. If you can get hold of a pressure gauge and measure turbo boost pressure at 3rd speed converter stall, even better.
Not necessarily. Quite frankly instead of assuming you need to get hold of a non-contact infra-red thermometer as suggested by Delmer in post #2 and get some hard data rather than perceptions. Here we are almost a page into the thread and there is no definite information to work with.
And if possible when doing the 3rd gear stall test have some one make a video of the machine so we can see the smoke and maybe hear how it sounds. You would need to up load the video to some place like YouTube and post link here I believe.
Thanks again..... I will be able to run these tests soon. Its too wet here at the moment. The info you guys have armed me with is great for me to attack it with so as to try to diagnose the issue. Will get back to you with some results.
Get the engine number just in case we have to pop down that rabbit hole at some point. Usually the system gives the engine number from the machine Serial Number but in your case it doesn't. It ought to be 48W-something. Arrangement will be 8N-1843.
The "thump" could be rear axle pivot bushings.
While it's too wet to work on the engine issue, what about having a bash at the "clunk".? I'd like to look first at two possibilities, the articulation hitch and the rear axle trunnions. 1. Articulation Hitch. (Install the safety bar before commenciong.) The illustration below shows the lower hitch with the front frame on the left and the rear frame on the right. With the engine idling raise the bucket about 3ft off the ground and tilt it forward slightly. Slowly lower the bucket to the ground and continue to power the lift function down until the lift cylinders bottom out. At this point the wheels will be about 6" off the ground. During this process watch the hitch for movement either front-to-back or up-and-down. If you can see either the hitch needs work done on it. Usually this is done using a dial indicator but I'm assuming you don't have one. Then repeat the same process with the upper hitch.
2. Rear Axle Trunnions. There are two trunnions for the rear axle, one forward of the differential and the other to the rear of it. See the illustration below. What you're looking for is wear in the fibre bushes (# 12 in the lower part of the illustration). To check this, get a couple of heavy duty jacks under the rear bumper and raise the rear of the machine slowly. You are looking for relative movement between the support and the trunnion itself, the dark line as indicated by the arrow on the photo. Just to orient you a bit better, this is where the rear drive shaft from the bottom of the drop box enters the diff.
I know SIS is good but just to let you know I do have Specification manual dated Oct 1979 and the Systems Operation and Testing and adjusting manual also dated Oct 1979 and the Dissassembly and assembly manual for the 3408 / 988B engine dated June of 1982 sitting by my left elbow. I was looking some on SIS earlier today and unless I was in the wrong area most of the 3408 engine stuff says 3408E which might be a bit different than a 988B engine was when new!
I know the 988FII started with a 3408 then went HEUI later in life. The correct info must be out there somewhere, just a matter of finding it. EDIT: I know what the issue is. There was a later TIER-I emissions re-power for the 988B using a 3408E engine. If you look in the Document Structure there are separate SysOp documents listed for both the 3408 and 3408E engines. See below.
Finally got a break in the rain today to get to ghe machine and try to get some readings. Here is the video link. Sorry if it is not good enough but will try for better readings if you need them.
A few comments in no particular order. The loader was built on 14th April 1979 BTW. 1. I really didn't see anything in those temps that freaked me out. Personally I'd have run it hotter until the gauge got to at least the start of the red zone or maybe even higher. 2. The TC out temp gauge (top right on panel) is not working, so therefore you have no idea whether the heat you see on the engine temp gauge is being produced by the converter or by the engine. That gauge needs fixing right off the bat otherwise it's not worth proceeding further. 3. You should shoot temps from the top to the bottom of the radiator (like you did with the engine stopped at the end of the video) from the back of the machine when it is heated up. The engine should be running at High Idle speed when you do that - try to do it as soon as the loader is put into neutral. That will give a good idea of how fast the heat is being removed from the coolant by the radiator. 4. Whatever you might think those air filters are waaaaay beyond ***ked. Replace both the primary and secondary filters ASAP. 5. Does the VCTC system work.? I see that the indicator light for it (in between the top two RH gauges) is missing. 6. As you pointed out the whole machine needs some TLC. A good pressure wash, greasing, fix the leaking lift cylinders and anything else that might be weeping. Right - $64,000-question. How much money is someone prepared to invest in this machine.? On the face of it it's not too shabby at all and probably wouldn't take too much to get up to snuff. But if the owner is a farmer who wants to fix it with lengths of baling wire and binder twine then he's fresh out of luck. It needs a few $$ spent on it, first and foremost to get the cab gauges working.
Thanks for that info Nige. I freak right out if needles on machines touch the red so was scared to take it there. But believe me it will go into the red very quickly if you keep working it once the needle reaches the high part of the normal working temp range. I was talking to the owner about it last night and he told me it has him baffled because it never got hot at all till it sat stationary with a flat tyre for a length of time. He said it never got hot before this.....even while working it hard on 115- 120° days ( the fact the temps stayed down no matter how hard he pushed it was the main thing he loved about the old girl ) He said it sat stationary for about 18 months ( longer than I first thought ) till he bought and fitted another tyre .... but he would start & run it for 20 mins it every couple of months to keep the batteries charged. It seems that there must have been something that the stationary sitting caused to now make it heat up once it was brought back into action. Yes it certainly needs some good time & money spending on it to bring it back to its former days. It does drive / steer / dig pretty well for an older girl. It needs to be driven back to the workshop so we can pressure wash it down & start repairs but its still too boggy yet. There is no visible play/movement in the centre connecting pins when the front tyres are off the ground and it is moved up/down...foward/back. But the revs need to be above idle to get it to change from forward to reverse. Where are the screens that need cleaning ? The toggle switch that switches it to full tourqe on the ' bucket raise ' lever doesnt work. ( the current owner has the new parts to fix it but has never got round to it ) Is this a solanoid or something more ? The ' test panel ' switch lights up most warning lights on the left side of the streering wheel but I have no idea if they actually work under operation. The video doesnt show the smoke coming out of her properly, but gives an idea of how dirty the motor is under load..... what do you think, ... is it overfueling ?... or is that pretty normal for an older machine with 19,000 hrs? How much above 200 deg can those motors run without being harmed ?
Your video showed a high of 190F on the upper water connection on both sides of the engine. That can go up to 210F provided the engine has coolant in it instead of just water. You completely missed my point about the TC Out temperature gauge. Without that working you’re pi$$ing against the wind regarding diagnostics. Quite honestly if that engine has 19k hours I’m surprised how little smoke it makes considering the state of the air filters in the video.
Get that trans temp gauge fixed and would like to see temp readings on both ends of the trans cooler
Cat’s parts support takes some beating, especially for those of us working out in the sticks. As an example, without leaving the comfort of my lounge chair, I can tell you that Hastings Deering have a TC temp gauge to suit that 988B for $141 and a sender for $61 in Brisbane. If they don’t have them closer, they could have these to you within a couple of days.
Did you check with the air filter out. I had field mice plug the air intake before the filters on a log skidder a few years ago. It gave me all kind of grief until I started it with the filters out and pinned down the place to look for the obstruction.
Here's a couple of examples of what it could look like with a bit of money spent on it plus a load of TLC.
Little bit of money? I've never worked on anything that size that didn't require money by the dump truck load.
Wouldnt it be awsome to have the funds to transport it into Hastings to have her overhauled like that ?........ I also have an old 922b that I would love to give an open checkbook to a Cat loving spanner handler and have them go nuts on it to bring it back to its former glory. Have finally been able to get to a town that has a Hastings outlet ( 500 kms from home ) so will try to get a few guages and other bits and pieces for the 988b to help solve the heating problem.
Just need to have a 966C to load the ten wheeler for the trip to the dealer!
Now where exactly did I use the word "little".? All I said was "a bit of money"........ Especially when considering the Certified Rebuild it's interesting to note than even a 30-40 year old machine can be rebuilt economically. That was the bit that somewhat surprised me.
I assume that one thing that may make a Certified Rebuild economical would be having a decent maintenance program that the machine had lived under for the first part of it's life. I'm just thinking about that other machine I commented on earlier, the WA600. I can't tell you how many times I heard the horror stories from guys, sub-contractors and dealer mechanics and even my boss, that worked on the other WA600 in the eastern part of the state about the condition of that one compared to ours. I know several years before I retired that one was taken to the dealer one winter for some major work. Not positive I believe it also was scrapped or sold while ours was and is still being used. Maybe not main line but as a back-up for the 988H or other work needing a, for us, big machine. If there was a Certified Rebuild for WA600's I would say the one I worked on from 1996 to 2015 would be a good candidate! Not that I or we did was anything all that special, just fix things as they came up and not having the crap beat out of it by the operators!
I know of two frame up builds done on WA600 machines at the dealer where I worked. The first was a customer rebuild and the dealer screwed the rebuild up by instituting a matrix pricing model to the parts prices so the costs spiraled. The second was an issue with a broken frame and wasn't really a rebuild. A new rear frame was swapped into a logger package and the machine went back to work. I only know of those two machines where that was done. The loggers down in Aberdeen only got components replaced as they wore out. All those had over 40,000 hours when they were sold at Ritchie Bros after they closed down the sawmill and export yards.
Finally got a chance to drive it back to the workshop. It took about an hour to drive back and coolant temps were high on the green section of the guage for about the last 40 mins of the drive. I got the point and shoot temp reader and took some readings at the transmission oil cooler while it was high: 198 ° entry 192° exit I visited the CAT dealer while I was in town and ordered the guages to replace the broken the conv oil temp, oil pressure, and fuel pressure as well as the stuff to fix the dash lights, new fan belts ect... these were not available to take home so I paid extra for them to send them out to me via post when they get them in. Also got 2 new low temp thermostats, gaskets and new air cleaner elements ( they had these in the shop ), so I can start the process of elimination. Can anyone point me in the direction of where the magnetic screens are so I can check them. ( I paid for the downloadable operator/sevice manuals but got ripped off. They only let me see the first 20 pages ...... the rest of the pages are blank so I cant see the pages for screens.)
If you went to that link I sent you to from the other 988 thread it's a genuine Cat website and you can't get ripped off. To download an Adobe pdf copy you have to click on the "Login" on the top RH side and when the popup appears click on the "Manage orders" hyperlink. See below.
Well here are a couple pictures: This is view from underneath, just need to remove the four 3/8 inch bolts on the bottom to slide it out. If I remember correctly this can be done with out draining oil. But Not 100% sure. And this is the picture out of the parts book!
Regarding the magnetic screens for the transmission, here's the relvant bit of the manual to get you going. NOTE: I think you will have to drain the power train oil before you can remove the screen unless you want a bath.
Thanks to both of you guys for that help.......I will get to it asap. I signed in as a guest & download the documents from the cat website. But for some reason even though I downloaded multiple times, the documents only show the first 20 pages. ( the rest are blank ). When I tried to download a fourth time again but the page crashed, and I can't find how to get back to my purchase as a guest. ( I didnt get a chance to write down my purchase number ) The site just wants me to buy the documents again to download. I started an account with them & signed in as a member to send them an e-mail about the issue so will wait to see if I can get another attempt to download.
Well if there are any more pages you need I might be able to send you some to get you through till Cat straightens it out. As always a full S/N is important to be sure info is correct!
Case of beer says pulleys are worn. For some reason these are common to slip and not make alot of noise. Belts will feel tight
Are you refering to the pulleys that are auto-tensioned by the spring ? I have a set of new belts ordered to see if they make a difference. I sprayed a heap of ' belt grip ' on the belts to see if it made a difference while it drove back to the workshop but it didn't seem to stop her getting up in temps. I havent studied that spring tensioner setup yet, but was wondering how to get more tension on the belts to see if tighter belts helped.
millarue makes a good point. The fan drive system is/was prone to wear on that type of engine, especially with a fan the size of an aeroplane propeller hung on the back of it. The grooves in the pulleys wear, so the belts sit lower and as a result the fan speed drops. Also the spring will lose tension over time. I'm guessing all the iron parts in the fan drive & tensioner are probably original. Your idea of trying to improve fan efficiency by increasing belt tension won't work if the pulleys are worn. NOTE: A bit of fan belt "squeal" when hitting the throttle is fairly normal, don't let the noise necessarily convince you that belt tension is the only possible root cause of the problem. Inspect all three pulleys - crankshaft, tensioner, & fan. Specifically look for where the v-belts sit in the pulley, the top surface of the belt should always be at least 3-5mm proud of the top surface of the pulley, and in no circumstances should touch the bottom of the groove. Also look in the grooves, can you see any sort of lip in them, or any type of "dished out" effect.? The spring on the fan tensioner was also updated after this machine was built. The updated spring Part Number is a 7N-5959.
I would look at the bottom of the grooves in the pulleys, if they are nice and shinny either the grooves are worn of the belts are worn.
Agreed. Bottom of the grooves should be rusty.
Thanks again for that info...... The bottom pully ( crankshaft was replaced a few years ago )
Take a good look at the tensioner pulley because it is smaller and therefore spins/wears faster, but don't forget the fan pulley while you're in there. Maybe use the new(er) crank pulley as a gauge for how deep the belts ought to sit in the grooves and base your estimation of wear in the upper two pulleys using the crank pulley as a yardstick..? It may be an idea to contemplate new pulleys for those two, new bearings/seals for the hubs, and a new tensioner spring. Believe me you do not even want to contemplate the damage that propeller could cause to the radiator if the fan pulley bearings ever let go.
But look at it this way once he fixed all that damage he would know the radiator and fan were not part of the heating problem!
Hardy ***king har .......... Although on a more serious note it did cross my mind to think just what sort of state the interior of the radiator core might be in if the cooling system had be run with the additive that is shown in the Youtube video had been in it for any length of time. Check out the video at 11:34, something "FLOC 2000". I wonder if the inside of the rad is all furred up..?
Alfloc 2000 corrosion inhibitor, by Nalco, is a nitrite based inhibitor. http://www.eclubes.com.au/products/download/226/product-bulletin-nalco-9518.pdf I'd be more worried it wasn't kept up, or the swamp water that might have been added too often, even mildly hard water will scale up if you have to add it regularly. Really it looks like the gauge doesn't want you to get it very hot at all, thermostats these days are 190. Have you inspected and tested the thermostats in boiling water? They tend to get removed when they shouldn't...
Just tested the thermostats in a pot of water on the stove. They both eventually opened .... ' On side ' themostat opened at : 95° cel ' Off side ' themostat opened at : 89° cel Both were very slow to open fully once the water boiled ( water was boiling for 40-50 secs before they fully oped. The new one opened fully at 89° cel and stayed open a lot longer while the water cooled. I purchased two new ' low temp' themostats as we work in high temp summers here. ( the new ones open at 76°cel ) # PICS TAKEN AS WATER COOLED AGAIN # The two thermostats at the top in the pics are the old ones.
The old thermos were slow to open at higher temps.
Nice, 76 C will work fine for you. I guarantee that your heater will still work great with the new thermostats Curious, do the old ones have a Celcius rating stamped on them?
Cant find any temp range stamped on them.....only the part numbers.
Been a while since I tested a thermostat but sure seems that those just starting to open at 96.3ºC are a bit slow when you consider that is 205.3ºF
In my experience they always open significantly well before their rated temperature. I would say you are definitely on to something here.
Which are..? The temp rating can be traced from the P/N. Let's not get too focused on the thermostats (although they might be a factor) because according to the OP the machine was "fine with no overheating" before it was parked for X months and the problem started when it was recommissioned. Now either the previous owner is telling porkies or there is something else going on here. My opinion - *other versions may be available.
The temperatures shown in the video weren't that high, driving it 40 minutes kept it at that high green range, the thermostats explain a good part of that. The black smoke is still a question, did it smoke consistently black when the air filter was removed? I don't claim to know what's going on, there usually is more to the story than the bit we get to hear. How long has this tank of diesel been sitting? not much help trying to figure out if you want to buy it or not, but I'd run it through a couple tanks before getting too worried, but then I don't run stuff that big either.
Here is the part number of The old thermostats. Can these things start not working properly after sitting for long periods
While replacing the thermostats, I discovered that the radiator was actually running a coolant ( I thought it was water ) and after a phone call with the previous owner dicovered he was running a CAT coolant. The inside of the thermostat housings and heads were in surprisingly good order ( no corrosion or rust growth at all ) I have flushed the radiator by draining it / filling it with water / draining agian / filling again / run engine till operating temp / draining it ect.... There was a little ( about a litre ) of brown/red fluid came out the drain hose at first but quickly ran clean again. No rust/shale came out. Previous owner said he had fushed and replaced the coolant a few years back. ( about 200 hours ago ) I would like to run it and do a bit of digging/work to see how the temps go now the thermostats have been replaced but one of the main lift rams is leaking very badly so will have to wait till I replace the seals in them.
Is that 191 on the pellet the temperature rating?
I wouldn't have thought so, unless there was something in the coolant that could cause them to "stick" if they were not opened and closed regularly. That would point the finger at the coolant itself being more of a a potential problem than the thermostats. 4W-4794 is the listed Part Number for this machine. Specs as follows:- Starts opening - 81-84C/178-183F Fully Open by - 92C/198F Minimum Opening Distance (A) - 10.4mm/0.41 inch. Same data for 4W-4011 Starts opening - 75-78C/167-172F Fully Open by - 89C/192F Minimum Opening Distance (A) - 10.4mm/0.41 inch. Both Part Numbers should fully open in maximum of 3 minutes when dunked in water @ 91C/198F and close in less than 6 minutes when hot and dunked in water @ 73C/163F.
One question I would have is what condition are the seals in for those thermostats? May not be critical but I always liked to install new seals when changing them.
When I ordered the new thermostats off CAT I asked the parts guy to give me everthing I would need to carry out the job. All he gave me was the thermostats and the gasket for the housing/head. When I pulled them off I discovered the inner brass/rubber seals. They looked in good repair and the rubber in them felt nice and firm ( no splits ect..) so I installed the new thermostats anyway.
I got a chance to pull the transmission screen. There is a small slice of yellow seal. Also some bits of fibreous material a bit like gasket paper/cardbourd. ( this stuff comes apart & and is very easily torn in two ). The magnets are coated in hairlike piles of very fine metal but there dont seem to be any chunks of metal at all......How do I get the inner core of the screen out so as to clean the round magnets ?
The fibrous material looks like maybe bits of an old gasket. The good news is that it’s not stuffed full of burned clutch friction material so that’s a good start. If it was you’d be in there with a shovel digging material out. To remove the inner core you have to pull it out pretty hard. The magnets will stick to the metal screen on the outside. You have to pull hard but carefully, the magnets are somewhat fragile. One person to hold the screen and a second to pull the magnet assembly out works well. Once you get the magnet assembly out take a photo. Some fuzz is totally normal especially when you have no idea when it was last removed. You’re looking for bigger chunks if there are any. To clean it, first wash it in diesel or kerosene until all the oily residue is removed. At that point you can blow the metal particles off with compressed air.
Maybe I was just lucky as I don't recall having that much trouble pulling the magnet assembly out of one of those screens. And I found a few that would scare the bean counters when the repair bill came in!Just wiggle it around a bit and it should come out if you keep the inner part centered!
That yellow piece looks like a piece of the soft o rings they used to use for transmission systems. hshansen is spot on about pulling the magnets out of the screen.
That’s why I suggested doing it with two people, one holds the screen steady while the other wiggles the magnet assembly out.
I tried for over an hour to get that inner magnet core out of the outer screen. The first magnet appears to be larger than the hole it is supposed to fit through. ( We are scratching our heads at this because that just shouldn't be possible ) On closer inspection there are small bits of metal like very small slices about 3 - 5 mm long & 0.4 mm thick ( no big chunks ). These bits along with the peices of old gasket & yellow piece ..... are on the outside of the screen ..... it seems like none of it are inside. Is this normal ? Shouldn't the oil pass through the inside of the screen first .... thus catching the material inside first ?
The screen was last inspected about 650 hrs of hard driving ago. The last owner had bought the machine to build/clean out dams. He told me he at all times worked the machine with the lever pushed to full torque. He pulled out the tque-converter and put in a seal kit when he bought the machine (ten years & 650 hrs ago ) I watched him drive the machine on a dam I had him clean out and he used to drive it hard. ( by ' hard ' I mean he never rammed it into a dirt pile at speed or anything, but was always going for a quick job ) I finally got the magnet screen apart ( had to bend the lip to make enough room for the magnets to pass through ) There was no chunks of anything inside the screen....only fuzz stuck to magnets. But after tapping the outer screen, some little bits of metal fell from the outside. These are very small and the larger peices are very thin and flat.
This is the biggest ' chunk ' ...... you might need to look at your own fingerprint for reference to the size.
This is the filings on the magnets after degreasing them. ( But before blowing them with an air gun to clean them completely )
Could I ask you to tell me which way this screen goes back into the housing on the transmission ? Should it sit this way up inside the housing or the other way around ? When I pulled it out in a hurry as there was oil running back down my arm & I didnt take notice.
It should be stamped "this end in" or words to that effect.
If that fuzz has accumulated in 650 hours it doesn't appear to be anything worth worrying about. Below is an illustration of a magnetic screen from a different model of machine, but it shows the correct orientation of the screen/magnet assembly with reference to the cover plate #1. Just imagine the whole thing rotated 90 degrees anti-clockwise and it is somewhat similar to your installation. #2 is the wave washer that keeps the whole shooting match pushed up against the suction tube, #3 the screen, & #4 the magnet tube assembly.
Regarding the larger pieces you found on the outside. This is logical, the oil flows from the outside of the screen to the inside then up the suction tube (on the RH side of the the above illustration). The "fuzz" will pass through the screen and be picked up by the magnets. The larger particles will not and (generally speaking) remain stuck to the outside of the screen due to the attraction of the magnets inside the assembly.
Thanks Cmark. It is stamped " Assemble this end in " on the outer sceen at the end that you place the inner magnet holder inside. I didnt know if the stamped words were in reference to the assembly of the screen/magnet holder or in reference to placing the whole thing into the screen housing on the tractor.
Thanks again Nige. That makes sense now......I was reading a downloaded service manuel that said that the oil was pushed through the inside of the screen so the magnets vvould pick up any bits of metal. That manual must be for another machine. Thanks for the diagram......If I am reading it right I should place the screen in the housing on the tractor ' magnet entry end up '. ( as it sits on the bench in photo ) By the way what are your thoughts on the bits of fibre/gasket and the small, thin slice of yellow o-ring ?...... are there any of these that would worry you ?
I wouldn't necessarily worry about them right now. TBH with your heating problem you don't need anything else at this time to deflect your focus from solving that. Keep the bits of gasket/seal on the back burner for now. Maybe at some time in the future the subject might get revisited if you get into transmission pressure testing. A thought struck me regarding your heating issue. Obviously getting a working converter temperature guage in the machine is absolutely essential, but I'm thinking you should also have a working VCTC system as well. Now with a broken switch and missing idiot light on the panel that's not going to happen tomorrow but it ought to be moved up your list of priorities to a point right behind "get a working converter outlet temp gauge fitted".........
Install the magnet tube/screen assembly as follows: - 1. Install the plain (non-rolled end) of the magnet tube into the end of the screen marked "Assemble This End In". 2. Install the compete assembly into the housing on the machine with the lettered end to the inside of the housing (upwards in your case). 3. Install the wave washer and the cover.
Yes I agree..... I have ordered and paid for the broken guages and also the green light bulb and lense for the dash. The old owner has the solenoid and other bits to get the switch on the lever going again. ( he bought the bits when he bought the machine but never got round to fixing it )
I probably missed but tried reading back through the whole thread twice, did we get a serial number for this machine in this thread? Not trying to panic any one here! Reason I ask is I recall we had to do upgrades our 988B torque converters. Checking in SIS it looks like the ones we upgraded were S/N 50W3100 and below. Does anyone have access to SMAU2382 I believe that is the Service Magazine that tells about the up grade to the impeller and related parts. One of the things was the converter was upgraded to 9 bolts from the previous 6 bolts. But making that change requires three somewhat major parts and not to mention those normally used to rebuilt the converter! Not saying this is need, actually may have already been done on a machine of this vintage. But in our application it was almost a given that it would be needed when the converter was in for repair during a transmission rebuild.
S/N I have is 50W03844. Not sure where it was posted. I’ll have a look at the SMAG later. EDIT: Here is the SMAG. Unfortunately it does not contain any information regarding Serial Number effectivity. The OP's machine was built in April 1979 so the chances are it was in the machines that should have been upgraded. Saying that does not mean that it was not upgraded at some time in the past though.
That is the correct serial number ( 50W03844 ) . When I was washing it down with the high pressure water, I noticed the remains of an old red sticker stuck to the ' on side ' of the transmission housing. Cant see any words written on the bits that are left, but its about 3 inches wide × 6 inches long . It gives me the idea that at some point this machine has had the transmission out for rebuild/repairs by someone other than CAT because, correct me if I am wrong, but as far as I know CAT don't use a red color in any of their stickers.
I think you're probably right, unless it was a Cat dealer sticker that was something like "reconditioned by Gough & Gilmour". It would need input from our Australian members to confirm. Post a photo, somebody might recognize it. Otherwise i think your assumption that it was a non-Cat rebuild is most likely correct. That still doesn't help with any confirmation regarding the converter upgrade though.
After reading this entire thread it seems as though the problem developed after the machine sat for an extended period of time. Did it have plain water in the cooling system during that interlude? Anybody suspect the trans cooler? Just thinking out loud here. Lots of good information here nonetheless.
I have thought about the trans oil cooler......and will investigate it if the other options dont pan out. I havent been able to drive it since changing out the thermostats becuase of a badly leaking lift ram that I have lined up to fix as soon as the seal kits get here. The system was full of caterpiller coolant while it sat and the inside of the thermostat housings were in mint condition ( no corrosion what so ever ) so I am hoping the oil coolers are good inside as well.
Out of interest what colour was the coolant that was in thre system when it was parked.? Your supposition is most likely correct that if the inside of the thermostat housings were in mint condition when you disassembled that area the rest of the internals of the cooling system are more than likely to be the same.
The coolant was a pink / red color but not bright......it had a diluted look to it. The previous owner said he ran cat coolant as that was what the owner before him ran in it.
If it was full strength Cat Coolant it would be bright red and totally transparent (not cloudy). The thing is that you don't need full-strength coolant in your climate to protect from freezing because that never happens. The protection is required against corrosion & boiling issues. It's digressing a bit but there is a product available now from Cat callled Extended Life Inhibitor (as opposed to the more common Extended Life Coolant) that contains the chemical package necessary to provide protection against corrosion & boiling but does not contain glycol for anti-freeze protection. https://www.cat.com/en_US/campaigns/awareness/cat-fluids/coolants.html
I’ve never had an issue buying ELC... here, it is no dearer than some of the offerings at Supercheap Auto at $110 for 20 litres of premix. I see the ELI concentrate is around $200 for 4 litres but haven’t found a dilution rate yet.
Yesterday I ordered 6 × 20 L drums of premix cat coolant. It Should fill the 105 Litre system and give me some spare as a top-up mix. ( $ 670.00 AU ) When it gets here, I intend to run the machine with rainwater for 15-20 mins two times to flush the system, before filling it with the coolant again.
New gages, fan belts & Full Torque dash light assembly arrived in the mail today. I didnt know these electric gages register temps witout even being hooked up ?
Ok.... got the gages and full torque light in. Question : Why do the bottom two gage needles flick right over to the far right when I turn on the key to test them ? The other gages flick to where they should with key on and motor not started/run yet. Edit : I answered my own question about the bottom right gage at least ( engine oil pressure ) The wire was off the pressure sender down at the motor. Dont know about the fuel pressure gage though ..... its wire seemed ok at the sender.
I've sent you the Electrical Schematic just in case you want to start tracing wiring for anything. Check your PM's.
Thanks again Nige.
finally got the seal kits to repair the badly leaking lift rams..... Very helpfull to have a little loader to pull the heavy rod/piston out of the cylinder.
Is that support under the bucket steel.? It’s hard to see what it is on a phone. A lot of weight up there, what with the bucket and the lift arms. Check the rods carefully for dings and scratches, otherwise you could tear the new seals out pdq.
We always used a heavy wall pipe under the center tube between the two arms and let the bucket be in full dump position. Believe we also had the pipe holding the arms up chained to the large lifting rings on front of frame. Also worked as much from the outside as possible. This was in a shop with very thick concrete floor so there was no chance of the pipe punching a hole through it. Also kept cones up to try to keep people from under the raised load, key word is "try"! Despite these and other precautions still was not the most comfortable job.
The bucket support is a piece of 100 pound railway line...... it is driven into the ground about a foot so the bottom cant kick out and the top sits into the recess of the bottom bucket pin mount. The bucket sits very solid in this position. It was tested in full float mode to make double sure it sat secure several times before anyone got under it.
That makes me feel a little better. In the first picture I was thinking it was just a 6X6 wooden pole. I'm not familiar with railroad track so have to reserve judgment on the strength of that, would it be right to assume it is not brittle type of steel?
Some can be brittle if it is a certain grade. This stuff has enough hardness to be very strong but not brittle. I wouldnt use it if it was a cold winter though.......dont know how it would go with that much weight & being frozen cold.
This big ugly home made spanner with a 12 foot length of 60 pound railway line as a lever still required a bucket pushdown from the the old cat 922b loader to get the 4 inch nut moving. ( 3 men swinging off the end couldnt budge it )
Check the Nyloc insert in the nut closely. The nut can re reused but if the insert looks anything like dodgy (imprint of a screw thread in the nylon) then get everything really clean and throw a good dose of Loctite at the threads of the nut. You’ll have to work fast tightening it once you get the nut screwed on the rod though. Thought. Will the eye of the lift cylinder rod fit into the tow bar socket of the 988.? If it will, slot it in there, block it up level, and use your small Jingaling loader to provide the push on the end of the spanner to tighten the nut.
Too late now for this one but if doing another it might pay to mark the nut and the end of rod, maybe with a little dot from a center punch. Then when you reassemble it just tighten till those marks are lined up again and you should be close to the original torque. This of course assumes you use same piston, rod and nut and there was no sign of any problem from it being not tight to begin with!
I tried to get the rod end into the towbar but unfortunately it just wont go in properly. I have done the nut back up by reversing the spanner on the setup in the picture and pushing down with the 922b loader. Now the fun of getting the new piston seal to go back into the cylinder.
Lots of lubricant and patience. At least in your climate you won't be battling the cold and have to install seals of a consistency somewhat akin to concrete........
This is a very good suggestion ...... I thought of the same thing myself.... AFTER ..... I already re-assembled the the thing. ( damn ) Will be doing the next ram like this though. I wish there was an easy calculation to do that would tell me the torque pressure I have applied to the nut. To get a final test measurement, after pushing down with the endloader on the end of the long bar about half turn from hand tight : I took the long bar off the spanner & put the right hand side end of 922b endloader ( 12 ton ) bucket on the spanner about 24 inches from the nut and pushed down till it lifted the right hand front tyre up off the ground ( about 3 ton ) without the nut moving ( tightening any more ). Anyone here good at the math on how much torque was applied by this final test ? 3 ton pressure 24 inches from nut = .......
3 tons@ 2ft = 6 tons @ 1 foot. Therefore 12000 ft.lbs. which sounds a bit on the high side. I think you'll probably have got it pretty tight though.........
Woo....12,000 ft pounds..... The manual only allows 3000 ft pnds +/- 300. I might have over done it then cause before the final test, I pushed the end of the 12 foot long bar ( 180 pounds in itself ) another half turn with the loader bucket after two men swinging off the end to hand tighten the nut . Hope over tightning doesn't mean
Well if the spec's call for 3000 ft/lbs and you have a 10 foot long handle on that spanner that's an easy one. Just get one 300 lb guy or two little 150 lb kids to hang on the end of the handle. 300X10= 3,000 and Bob's you mother's kid brother! Or just divide the 3,000 by the length of the handle and that tells you how big a guy you need. Wish I had the old service manual for the 74TD Euclids we had at the quarry in the 1970's. That book gave the torque for the rear axle wheel bearing nut as "a bar so long and a man so heavy on the end of it"
When the lift cylinder repairs are completed and everything is back together I suggest the next step should be to adjust the kickout on the Lift function to make sure that the lift cylinder pistons don't smack hard against the heads of the cylinders every time you raise the bucket up to full height. My only worry is that electrically-speaking it may not be functional or bits may be missing from it. Oh the joys of older machinery.........
One suggestion on getting that piston back in the barrel. Take some nice clean and shinny thin sheet steel, maybe some piece of stove pipe. Just needs to be a bit longer than it needs to wrap around the piston. Make real sure there are no sharp edges on it. Wrap it around the piston and hook together some screw type hose clamps and tighten them down centered right over the seal. Let it set like that for the time you are getting ready to put it in the cylinder. Then remove the clamps and the stove pipe. Oil it up and if you go nice and easy keeping things lined up real close it should slid in pretty easy. Of course you have the chamfer at the top of cylinder nice and shinny and the hose or line to the bottom of the cylinder off, not just loose right? No sense in fighting the air pressure in the cylinder on the way in! Don't try to rush it and it should go in with out too much work.
I cant see the lift kickout adjustment anywhere on the loader. The lever detent valves under the levers in the cab are stuck solid..... I will have to look into getting some new bits.
The instruction that came with the seal kit says : " before installing piston ring onto piston, place piston ring into bore "...... I am not sure why this is done. But I have forced it into the bore a little and left it there an hour. ( it was as hard as heck to get it in there even though it isnt even on the piston yet.... my theory is it must help force the ring seal to contract a bit before fitting onto the piston for reassembly ??)
That's what I was afraid of. Was there a Parts Manual amongst all the documentation the former owner handed over..? You need to be looking for the "Bucket Positioner Group". It covers both Lift and Tilt function kickouts. It may help you for the next one but dunking seals in really hot water always seemed to help them fall into place more easily.
I did look up the position kickouts in the manual, but cant see the loader arm kickout positioner anywhere.....I think maybe it was taken off by some previous owner.
I didnt have any shiny steel like you said but made up this ' hose clamp ' type of thing out of some springy pallet strapping steel to squeeze the piston ring while I things set to reassemble the cylinder. P.s. The bottom cylinder hose is off.
Got it back together this evening. Question : Do I need to crack a bleed off so the air in the cylinder can escape once I start her up & ttry to lift the bucket off the support pole ?.....or is it ok to just start it and play with the levers ?
No need to bleed anything. This applies to any empty hydraulic cylinder. Work the cylinder(s) s-l-o-w-l-y in and out several times, stopping before the end of the stroke. After maybe five or six strokes, start to dead head them, gently at first. Top up the hydraulic tank then you should be good to go. In your case with one cylinder disconnected, leave the rod unpinned and carry out the above procedure. As the cylinders are connected in parallel the one with no load will happily move in and out without troubling the other one. The other advantage of this is that it will be much easier to line up the pin. Fine adjustment of an air-filled hydraulic cylinder is difficult if not dangerous.
Thanks for that info Cmark. I know very little of these things, I have driven all sorts of machinery over the years but this is the first cylinder I have ever repaired so am a bit cautious to do it right.
Good on you for asking. Most people would have just blindly crashed on and only asked for help when they were up to their neck in the swamp.....
While my suggestions should not be a problem, think it might still help some, I guess it has been a long time since I did a 988B lift cylinder back in the dark ages the outer ring was not split and you had to stretch it over the piston and compressing it was very important. Main thing is to go slow and easy untill the piston is all the way in and if there is any doubt stop and check things out.
If you don't have the service manual with the kick out information let me know I have it saved to my computer.
Thanks kshansen. Will do. Cant say how great it is to have you guys sharing your years of knowledge on this projects like this one. Its a real time/money/stress saver.
At the risk of sounding over cautious.......here is another question : I fired up the 988 and worked the hydraulics slowly till they were working good, then drove it over to the paddock near the shed ( about 150 yards away ) & gave it a bit of work at light digging/reversing/fowards ect...for about half hour. I idled it down, rested the bucket on the ground & shut it down. I then took the filler cap off the hydraulic tank and as I unscrewed the cap it was pressurized with air. ( air was escaping from the tank through the cap-threads as I took the cap off ) Question : Is that normal or does the tank have a breather that is blocked ? P.S. ..... there was no sign of any heating problem with the little bit of work it did. The coolant temp needle sat about 5 mm into the bottom of the green. But I will hold my hopes that the temp issue has been solved till I put it to real work building a dam within the next few weeks.
Is this your tank..? The tank does not have a breather. Look at the section A-A in the illustration. That is a relief valve to prevent the tank pressurizing excessively. In your 988B the implement pump suction is above the oil level in the tank so the design is for it to pressurize once the oil gets hot. This assists with oil flow into the implement pump suction side. Provided nothing is stuck in that relief valve you should be fine. Strictly speaking you should only unscrew the tank cap when the oil is cold.
In general all hydraulic reservoirs that aren't plumbed to air compressors are made to draw in air as the fluid level in the tank goes down when the piston sides of the cylinders fill up. It forces fluid into the pumps helping to prevent cavitation.
It does look like this tank. From this illustration and explanation I gather Since the pressure in the tank wasnt excessive when I took off the cap, I am going to assume everything was normal.
Thanks John C ....... thats a good explanation of how it works.
Not to argue here but I'm thinking that A-A illustration is the oil filter cover and the springs are, one to clamp the filter in place and the other is the by-pass valve for the filter. If I'm not mistaken the pressure relieve valve for the tank is actually the item #5 in that drawing.
Isn't the relief valve for the tank the what they sometime call the breaker? Or in this case just simply "VALVE-BREAKER RELIEF" Item #29 in this picture of a another S/N range 988B?
That's it.
You're right Ken. The breaker relief valve functions as a relief valve when the pressure gets too high and as a "vacuum reliever" if the pressure in the tank gets to the point where it wants to suck air in from outside. It's designed to relieve at 20+/-3psi and suck at 0.3+/-0.15psi of vacuum. Suggest to pull it off and see if it the vacuum side opens when you suck on the threaded end. If it does at least you know the internal mechanism in it is moving and I guess from that test you could assume that it's relieving correctly.
Thinking about it you could test it if you were so inclined by rigging up a regulated air supply from your air compressor. Remove the breaker valve and hook the air supply up to the threaded end of the valve that screws into the hydraulic tank. Crank up the regulator slowly and see what pressure is on the gauge when the valve finally pops off. DON'T go above the maximum specified pressure + tolerance, in other words 23psi. If it doesn't blow off before that, it's fcuked. Get another one.
Just an update on this ...... Put the new thermostats in, new fan belts, new cat coolant, re- sealed both the lift rams, drained the transmission, engine & hydraulics & refilled with new oil. ( ouch.... $$ ) Then put her to work building a new road, through the property, clearing about 7 kms of fencelines, then building a new dam wall across a small rock gorge so the cattle/native animals have access to water in country that has remained waterless till now. Also put about 10 hrs into building a large earth tank. The old 988B ran well and temps stayed within the green on the coolant guage. Here is a video of her working the dam project.
I'd rather hear the machine....the sound is as much a part of the job as the visual
Yes on the sound, only thing worse would be if this was a 12V-71 Detroit and he put that music on to block the Buzzin' Dozen Music! Not that a 3408 running hard wouldn't sound good! Heck I'd love to hear a D399 genset going through the passes of a load test!
Welcome to the world of running Big Yellow Iron Another vote to get rid of the music.......... On the other hand I'm glad to hear that you finally seem to be getting on top of the issues with the machine.
Haha..... should have gone with gut feeling that you guys have diesel running through your veins & would want the authentic version with all the engine noise. ( will upload that as well for you ) One issue I do still have is that I can't get the new ' converter oil ' temp guage to work properly. I think it is the sender unit but cant locate the exact position. I would appreatiate it greatly if anyone could point me to where it is located.
Well hard to find one easy to see picture! It is mounted in a valve on rear of converter and has a large steel line going back to the oil cooler. Hope these pictures help! This above is the best picture of the valve, arrow point to the temp sensor. Here is a picture out of prts book showing the two steel lines heading to the oil cooler to the left of drawing. And this last one shows the cutaway of the valve itself. Arrow shows where steel line connects. For size comparison the bolts on either end are 3/8 inch with 9/16 heads. The temp sender would be just below the plug marked #1, someone cut the boss off for the picture! And just because I know you were going to ask here is the parts book section showing the sender. Note that in the list item #10 is for torque converter temp and guess what item #3 is for water temperature. Notice something about the two of them?????? Now I'm just wonder when someone will ask about item #9?
I’ll bite. What does that solenoid do Ken ?
Hey thanks for that Kshansen......I was looking all over the front of the converter and the transmission housing. I thought there would be an obvious wire harness to follow to it but it seems to be hidden out of obvious site.
Well that converter is a "variable rate converter" and the solenoid is so you can leave it set in the lower torque position and when you need more torque you can just work the switch on the control lever to get max torque then click switch back off to go to the lower setting. I'll see if I can find the "official" description on sis!
Variable Capacity Torque Converter (VCTC)..?
Well Cat decided to spread the description over four files! Attaching them here:
Yep I stand corrected VCTC is the "official designation!" And the early ones from the 87A 988 and early 988B's did tend to give some problems till they went from six to nine blots holding them together inside. Did many of those upgrades back then. If any one wants the full "Systems Operation" on that convertor it is about a 15 page PDF that I just happen to have saved!
Heck you guys are helpfull........ I had been going to research where the vctc solenoid is located so I can get the switch operating again ( nothing happens when you hit the switch ). Question : Would the solenoid be the only cause for the switch not working ? Or would there be a couple of things to check first ? Kshansen, is there a way that could I get that document off you please ?
Here is the version of the video that has no music as promised.
Well first thing I liked to do to test that system was to put the control lever for the convertor in the "Minimum Torque" position and have the switch in the off position. Not sure if your machine has the rocker switch on the bucket control or the floor mounted switch. Then either stick bucket into a stone pile or apply the right brake pedal and do a stall test, give it full throttle. While doing this just work the switch on and off. If the solenoid and wiring is working you should have a good indication of the engine coming under more load. There should be a light on the dash that indicates when switch is in on position also. Guess I need to do a bit more research on your machine's wiring, yours is the 50W03844 S/N right?
Sounds better but I was getting a bit worried near the end with it working on the side slope, seemed to be a little tippy! And looks like someone needs to work on the right ladder!
Thanks Kshansen...... This 988 has the rocker switch on the lift lever. The green light was broken when I got it and has since been replaced ( green lens and bulb ) but it does nothing when the rocker switch is activated. Yes, the serial number is 50W03844
You've got mail!
I did send the OP the appropriate electrical schematic a while back Ken,
Well now he has two copies, between those and the other files I sent him he should have enough reading to keep him busy for the weekend!
Thanks for that Nige I remembered & had a look and found the copy you sent to me.
I have carried out this test & can say that there seems to be no function of the vctc switch at all so I have purchased a new solenoid for the vctc switch....... question : Where is the solenoid located ? I cant seem to locate it.
sit on left rear tire pull panel it's on torque converter housing if I recall
Thanks rmllarue. I assume you would mean ' left rear tyre ' while I am facing the direction the machine is facing. I cant see it anywhere ...... I am starting to think it has been removed and blanked off with a bolt or something as I cant even see a wiring loom anywhere near the torque converter.
Also does anyone know what would be the correct operating temp range ( in degrees ) for the torque converter/transmission ? I purchased this electronic engine/transmission temp reader and rigged it in the cab so I can see the exact temps while it works. While digging hard in pleasent cool weather : The engine sits between 75-80°C ( temp Sensor bolted to the thermostat cover on left side head ) The Torque converter is between 95 - 98 °C ( temp sensor bolted to same spot the oil cooler pipe leaves torque converter) https://www.ebay.com.au/itm/WATCHDO...375385?hash=item2163afa1d9:g:-g0AAOSwk5FUryTS
Not sure but from memory, this looks like a different torque converter than mine.....I will see it again this afternoon.
As for the converter look at this picture, I rotated it so it should look like what you would see when sitting on the left rear tyre. Just for sake of keeping terms somewhat straight when referring to locations on a machine there are in relation to the operator sitting in the operators seat. The one main exception to the rule(there is always an exception right?) the right and left of a motor is while you are standing at the flywheel end of the engine looking toward the fan end, so yes the right side of the engine is on the left side of the machine! Anyhow here is the picture that I marked with some colored stars. Blue star is on the top of the converter Red star is on the solenoid the two terminals are not easy to see but one is above the star and the other below the star. Green star in covering the hole the control cable goes in, that would be the cable that is connected to the handle behind the hoist and bucket levers in cab.
I took way too long to find information on the temp but finally found something: If text at the bottom is hard to read it says "The indicator arrow will be in green area 33.5ºC to 129ºC, during normal operation. So if you are running in the 95º to 98ºC range I'd say you are good.
Thanks kshansen.....as always, brilliant infomation. ( almost broke my brain trying to find that info ) As I suspected someone must have removed the vctc solinoid as there is none at all on my torque converter in the location that you have marked with the red star.
What is the part that has the red circle around it in this pic ? ....... The torque converter on my 988b doesnt have this part .... or .... the solenoid....or any wiring for them.
I'm hitting a dead end! SIS is only showing parts break downs for the 988B so trying to get any good information is a problem. Not sure what that part is that you have circled, I seem to recall that the valve it is mounted to is valve that controls flow to the converter cooler. Any chance of some pictures of you converter? Is this what the converter looks like on your 988B? Note that this picture is out of a 988 not 988B manual! The solenoid for the "full torque" can be seen just a bit below and to the right of the plug for the "F" pressure tap.
That thing circled in red is a temperature sensor.
Okay must be a different s/n range than I'm familiar with as the ones I recall were like this #3 in the poor picture from SIS below: and one more lousy picture from SIS: Sender is between the two bolt holes at the bottom of picture!
The solenoid that I have been sent from cat has to be screwd into an opening of around 1inch diameter. I cant exactly get a good pic of the torque converter at the moment as its hidden behind dust caked oil ( oil spill ) & what seems like a hundred different pipes going in all different directions.
The solenoid should be part number 4V1222. Circled in red below" I always found it easier to remove and install by removing the nut that is in the center of that tag with the numbers on it and slide the coil with the two wire terminals off then use a large socket to unscrew the part from the valve body. As I recall that 45º elbow just above it in picture is in the way of the wire terminals. Plus the hex at the bottom of the valve is so thin it's hard to get a wrench on good. Also right where the "F" is located in that picture would be where the control cable from the cab control lever would come out of the top of the valve. The small red arrow points to the bolt you need to remove to get the cable to slide out of the valve body.
Here's another view of the same valve, it's a bit grainy but best I can do from SIS. From this angle you can see the hole the control cable goes in and a different view of the solenoid valve. Cat refers to this complete valve as the: Sequence And Pressure Control Valve
I installed this electronic temp reader into the cab so I can see exactly what the engine and Torque converter temps are doing as I work the 988b. The device has an early warning alarm that can be set to go off at a pre-selected temp before things get too hot. I currently Have the alarm set as follows. Engine early warning Alarm : 95° Cels Transmission early warning : 98° Cels. Yesterday I was working the machine with 5 hours of hard digging and the weather warmed up quiet a bit in the afternoon so the temps climbed along with it and the torque converter 98° cel ' early warning temp ' alarm on the new device kept going off. The torque converter sat almost exactly 20° cels warmer than the engine temp. According to Cat, the correct working temp range for the torque converter is between 33° - 129 ° Cel .....( green color on dash guage ) What is your recommendation at a good ' early warning temp ' to set the new device at so It doesnt go off when unless things are starting to get too warm ?
Personally I'd set it at somewhere around 115 DegC and see how it goes. You might have to go to 120. A Level 3 warning on an electronic (modern) machine generally goes off around 125+ DegC. Your old girl probably needs a little bit more babying than that.
Thanks for that advise Nige. I set the transmission alarm at 105° C today but being a slightly cooler day it never climbed higher than 98 °C.
What to watch is how fast the converter outlet temperature drops once you take the converter out of stall after filling the bucket. The way it falls is an indication how well the cooling sysytem (especially the transmission oil cooler) is working. the TC out temp will never go down to the same temp as the coolant but it should get within maybe around 5 degrees of it at best.
I have the new electronic Transmission temp sensor placed on a bolt where the oil leaves the converter to be directed to the oil cooler. With the work it is being asked to do, the loader is pushing in 1st gear into unbroken hard rock/dirt till the bucket is filled, then straight into reverse up out of the excavation hole to run a short distance to dump onto the dam wall then back into the hole to hard digging again. So far the converter temp doesnt seem drop as soon as the bucket is filled & the pressure comes off the torque converter a short moment to go into reverse.......both the coolant & converter temps drop a few deg while I am spreading the dirt/rock along the dam wall ( not hard pushing ). The temps seem to be consistantly about 20 deg C apart while working hard with the engine temp being the lower of the two. For example if the engine temp is 78 °C... the torque converter will be 98°C. The converter seems to go between 93°C - 100°C depending on how hard it is being pushed once it has warmed up properly . 95°-98°C is where it seems to spend most of the time once it has done an hour of work to warm up properly. Is the oil outlet on the converter the best place to have the temp sensor for best temp readings ?
Apologize for the grainy picture but it's the best I could fine fast on SIS. This is the valve on the back of the converter that Cat installs their temp sender in, see the red arrow there should be a steel line going to the converter from the port on the left side of the valve as it is positioned in the picture. PS:When I say "back" of converter I do mean the side facing the cab, I think of front and back and right and left of engine as somewhat separate from those terms relating to the machine itself. Front of engine being the end the fan is on and the left is as determined while standing at the flywheel end looking over engine towards the fan end! One thought I might have is if your temp gauge is using one of the bolts as a point to read the temperature as opposed to having a probe right in the flow of the fluid there could be a bit of a delay in reaction to the temperature of the oil as the casting of the housing would need to cool down before your sensor could read it. Maybe Nige or someone else could word that better or expand on the thought!
Yes I think you would be right about the sensor only picking up the housing temp and not the oil temp directly. I have finally located the temp sender for the TC dash guage but unfortuninatly the wiring loom that goes to it & the vctc solenoid is missing. I might try relocating the NEW electronic sensor onto the original TC temp sender and see if it picks up more of a direct oil temp seeing as how the TC sender has the end in oil flo. The white arrow on this pic shows where I currently have the sender.
View attachment 222827 View attachment 222827 I think I finally located the wiring loom that goes to the vctc solenoid and Converter oil temp sender......it was wrapped around up against the chassis on the right side of the engine ( facing the bucket from cab seat ) . After investigation I found out that the previous owners cows got to it and ate some of the wiring while it was parked in a cow paddock. I repaired the ends with some new eyes and hooked up the correct wires to the new solenoid to se if it would engage ( click ) with the swith on the lift lever being activated. I couldnt get the switch to cause the solenoid to activate or make the green light on the dash come on. Whith the wires hooked up, if I pressed the solenoid terminal with the red wire attached against the engine exhaust manifold, it would click and activate the green dash light..... it wouldn't do this while pressing the solenoid body against the manifold and activating the lift lever switch. I then pulled the lift lever apart to look at the vctc switch. There is a red and black wire that goes to the switch with no other wires visible. Does the switch not activating the solenoid mean it is dead ?
I circled the fitting the temperature gauge would go in if you had a mechanical gauge, if an electric gauge then the sender would be in that location.
Just to refresh my memory, do you have an actual wiring schematic? Not just the one in the parts book? It's been many years since I worked on one of these but there are diodes in the wiring of this machine and I see at least one in the wiring for the solenoid, not saying that's the problem but it does add a level of complication! Right now I'm having trouble following the wires on computer screen and may at some point have to print it out to be able to follow the wiring on paper!
Yes Nige sent me a wiring schematic for the 988b. According to the sis parts documents, the lift lever handle vctc switch has a wire that runs to earth.......I will need to check that hss a good earth. I will take a test light to see if the switch is recieving and allowing power through. By the way........there is a Cat electrical engineer somewhere who deserves the Caterpiller Award for : ' Best invention to cause total frustration to anyone who pulls this apart and tries to re-assemble '. That spring idea listed #2 is a proper pain in the ---- to get to stay in position while trying to get the handle back together.
Just an update on the vctc switch and solenoid : After pulling panels, pulling apart the lift lever handle again, pulling the instrument panel, running external wiring to do tests ect.....turns out that the switch in the lever is faulty. I got another switch from the vehicle, hooked it up to the original switch wires and the green dash light came on and solenoid clicked when I flicked the switch. I then set about the unpleasent task of removing a 2 inch steel oil pipe thatruns from the pump in the center of the engine to the screen housing on the transmission. Cat run the oil line right in front of where the vctc solenoid has to be threaded into the housing just close enough so you cant get a socket onto the solenoid to tighten it up. After hours of struggling to get my hand/tools in past the other hoses ect... to get whats left of the old solenoid out, new one in and wires hooked up ( including the torque converter temp wire ), I now have the vctc solenoid and green dash light going on and off at the flick of a switch. ( non-Cat switch till I can get the real thing ) Thanks to you guys for sharing the needed info so I could find the parts and locations of the needed repairs.
I always liked the dash panels on those 988B's take out a couple screws and loosen a couple others and you could unplug the harness and take down on to bench to clean up and work on them. Much better that trying to stand on head under dash of a loader! Also nice that someone thought enough to color code the plugs! Looks like yours needs a little patching with some fiberglass cloth and epoxy! And a couple wires look to be cobbled up might want to keep an eye on those!
Always nbice to hear a success story.
I just noticed that 2 injector lines have started weeping a little down the outside of the rocker covers on the 3408 engine. The two injecter lines have a little movement at the rocker cover when I push/pull them. ( no movement in the others ) I put a spanner on them but they are tight. Question : Is there a seal between the inner & outer fuel lines or would this be a cracked injector line causing the fuel leak ? ( Pic is not my engine but its one I found on the internet to show where the leak is.) Also I have to pull one of the steering cylinders to put a seal kit in. 2 Questions : 1. Can I articulate the machine, ( chocking the wheels ) pull the front pin and pull the rod/piston out of the cylinder without removing the whole cylinder ? 2. Which direction will the pins come out .... up or down ? The pins are very tight. ( I imagine the pin should be forced upwards direction )
1. The leak is engine oil I presume? There is a seal on the adapter that goes through the rocker box. This point may or may not be related to your leak, but it's important to keep all the injection line clamps present and in the correct place. 2. The steering cylinder pins are tapered and come out from the top. My preferred quick-and-dirty method for removal is to put a jack under the bottom of the pin then hit the clevis with a sledge hammer, much the same as releasing a steering ball joint in a car. Can you get enough clearance to get the rod out by articulating the machine? I'm going to say a cautious yes. It's been a long time since I worked on a B series but I seem to remember that perhaps one side will and one side has the hydraulic tank in the way???
Thanks for that info Cmark 1. Now that you mention it I didn't actually check if the weep is engine oil or diesel. I saw it and assumed it was diesel so will check to make sure. The engine runs fine so it might be engine oil getting through the rocker cover seals. By " injection line clamps " do you mean the clamps back near the governer area ? 2. I thought the pins might have been a tapered pin. I have a 15 ton puller that I can also use as a press to have a go at them. I might try you method first as well. It is the cylinder on the fuel tank side. ( left side if you are sitting in the drivers seat )
By clamps I mean the clamps on the lines between the injection pump and rocker boxes. They appear to be in random places but are actually carefully placed to eliminate harmonic vibrations. Without them, leaks and broken injection lines are guaranteed. By all means have a go with your puller but I usually find that a 50T bottle jack pushing hard enough to take the weight off the tyres is necessary.
50 ton jack ..... take the weight off the tyres...... heck..... I may need a lot bigger jack to get that little pin out then. I only have a 20 ton bottle jack.
I'm pretty sure you can get the rams out of the cylinder on the left by steering it all the way to the right. One point that may not be obvious is that it will help to let the ram come out if you remove the hose from the back of the cylinder so you are not fighting suction from that end. One idea to keep in mind for those tapered pins. If you at some time find one where the pin has come loose and wore the tapers it can be difficult to repair that taper, not sure how one would do it in the field, what I recall having done on a couple machines was to bore the holes for a straight pin. Believe we had a bushing made for the top side as that is bigger than the pin. Then once that bushing was installed line bored it and the bottom bore to accept a straight pin. Not a perfect solution but sometime you do what you have to do!
Just an update on the steering cylinder repair : Used a 20 ton bottle jack to remove the pins out. Didnt need to flog the lugs with a hammer, they just popped out. Front one took almost all 20 tons of pressure before it popped loose though. Found out the fuel tank side rod/piston cannot be removed while the cylinder is still pinned. There isn't enough room beside the fuel tank to swing the rod end out far enough to get it past the front half of the loader. ( Must remove the whole ram ) I used the front pin lugs to hold the ram while we removed rod/piston. Also used the front lugs, the tray of the work vehicle & a peice of cut timber to hold the rod while I broke loose the nut that holds the piston. Looking at the difference, I think the hydraulic tank side steering cylinder may be able to remain pinned in the machine while it is repaired. There seems more room between the the ram and the hydraulic tank to be able to swing the rod out far enough. The cylinder is not leaking on that side so wont be rebuilding it yet to find out.
If only doing one side at a time I seem to recall on some machines all you had to do is steer all the way say to the right then work on left side. Then if you need to do the right side put the left one back in and steer machine to the left then work on the right. Also if you block off the lines to one cylinder you can steer the machine using only one cylinder as long as on smooth surface, but it will actual react faster when it only has to supply oil to the one cylinder.
I tried to get the rod out with the machine articulated all the way but it was still about 4-6 inches too close to get the piston out of the cylinder. The fuel tank stops the cylinder from being pulled out enough.
Well it's been a decade or two since I had the pleasure of doing that job so might have been thinking of some other Cat!
I thought for a moment it was going to work.... but no show. By the looks of it I think the hydraulic tank side steer ram might be able to be re-sealed with it still pinned. The hydraulic oil tank looks far enough out to pull the rod past the front end.
G'day all. I am getting more tourque converter slippage lately than usual. I have heard that there is there a way to retrieve some torque by adding a shim to the converter clutch control valve at the end of the variable torque lever cable. Is there anyone here thhat has done this ? Thanks in advance.
Have you tried setting the correct adjustment on the control cable as a first step.? Also I guess it would be a good idea to check that the cable is well-lubricated and is not binding. See attachment.
Thanks Nige. Yes I have adjusted the cable and it seems to be sliding inside the sheath ok.
In that case the next step would be to get into the Sequence & Pressure Control Valve and check all the springs to see if they are "tired". Most likely they are, I'd speculate they are probably original. After that test all the converter pressures, especially the Impeller Clutch Pressure. See attachments.
Thanks for that help Nige. For some reason I cant download the files you uploaded. I have a complete workshop manuel for the old girl so I should be able to find it in there.
You need to be on a PC or a laptop and download them to the desktop. Some smartphones don’t like them it seems. They are only Adobe pdf.