Hello everyone - Long time lurker, first time post. I recently purchased a Cat 955L S/N: 64J5699 E/N: 48V2443 The first thing I did was sent it to a shop for a full PM. The loader was running good as I was clearing some wooded area for a road. I got too close to the creek and got stuck. As I was using the bucket to push myself out, the loader shut down. I took off the side panel and noticed that some mud/stick or something had kinked the fuel line about 5 inches from the engine. To get the loader out to be fixed properly, I cut out the kink and spliced in some 3/8" rubber fuel line. It would start, and run for about 30 seconds then die. I thought perhaps there was another kink so I ran rubber fuel line from the tank to the engine. This didn't help so I started checking the fuel system. First thing I noticed was that the primary fuel filter had not been changed or cleaned. It was very nasty, but the fuel in the main fuel filter looked good. Cleaned the primary off the best I could at night with either. This is when I noticed the primer pump did not work (no resistance, like bad o-rings). I bought a new primer pump and primary fuel filter. Bleed system and tried to start - nothing. I put a pressure gauge on the filter housing and get no pressure when I start it on either. The next practical thought was that the transfer pump had trash or something. Purchased and installed new transfer pump. While I was changing the pump I used 2 cans of carb cleaner to make sure every orifice I could find was clean. Now I can start the loader with either and it will try to idle for about 2 minutes then dies. I thought maybe the transfer pump was sucking the rubber hose closed, so I used 1/2" braided line and a 5 gallon jug to bypass the fuel tank/rubber hose rig I had before. Same results. I have put my finger in the rack as the throttle is moved and the rack seems to be moving. I am fresh out of ideas, just trying to escape the $225 truck charge and $135/hr tech charge. I have worked on cars as a hobby for most of my life. However, this is my first big piece of equipment so I don't know what is going on. The system from the tank to the rack seems super simple, but I am missing something because it is starving for fuel and no pressure at the filter housing. Any suggestions would be appreciated. Thanks,
Recheck the serial number, I use to seeing 2 numbers and a letter, not 3 Might have air in the fuel lines, have you tried to crack the injector to see if fuel squirts out
Thanks for the reply. Fat fingered s/n. 64j I have cracked lines at pump and head multiple times to bleed.
Is the fuel line free flowing to the filter not trying to be smart but do you have plenty of fuel in tank had a customer pull injection pump and have rebuilt still would not run called me out only to find out he was out of fuel
It runs on either (good but bad for the motor) so it is fuel issue My 955 is gravity feed so along the same comment as Dave, there much be enough fuel in the tank. I had a heck of a time bleeding mine the first time after changing the filter. When using the 5 gallon can, was the can placed high to provide a good gravity feed?
Serial number is showing up from France and a D330T but close to change over to 3304
yeah, plenty of fuel. I didn't have the diesel jug up high. About same elevation as fuel inlet. CAT guy told me SN showed it was built over seas. The tag shows 3304.
Here is a pic of the tag
Here is the current situation
do you build pressure with the priming pump now
I don't know how much pressure it should be, but I break the lines loose, pump a couple times and fuel comes out with no bubbles. Tighten lines. I do this at the pump first, then repeat at the head. Seems to be well primed. It will idle (rough) for over a minute so even if all the air wasn't out it should have picked up fuel by then.
With the lines tight, how many strokes of the priming pump does it take before it goes rock solid.? That’s what it should do on a good system.
The primer never gets hard to push. You can tell a difference between an air push and a fuel push. It gets resistive but never anywhere close to solid.
Primer pump should get hard with lines closed Can y6ou get someone to help you and try pumping primer wile you start it see if it runs with you hand pumping the primer
I just worked on a D6 could not get primer to pump turned out the line that comes from the bottom of injection pump to primer was plugged with junk pull lines make sure they are clear also did you open up the bleeder valve on top of the filter housing a pump until you get clear fuel running out
The primer pump does not get hard. I would say I feel resistance, but no where near stiff or hard. I have tried to pump the primer while running and it doesn't help, just prolongs the rough idle. I have cleaned all of the lines on the primer and every orifice. When I bleed the system - I open the bleeder valve on top of the fuel housing and use primer until I see fuel and no bubbles. Close bleeder valve. Open fuel lines at pump and use primer until I see fuel and no bubbles (a few strokes). Close fuel lines. Open fuel lines at the head and use primer until I see fuel and no bubbles (few strokes). Close fuel lines.
Do you have a fuel pressure gouge on the dash if so does it get out of the red It sure sounds like a fuell supply - pressure problem
I connected a fuel pressure gauge directly to the fuel filter housing (this is where the dash gauge reads from). I am getting nothing. (Yes the fuel gauge is good). I know I should get 25-32psi at full throttle, but I don't have any numbers for cranking or idle. However I expect it to be more than zero. I have been traveling for work. That coupled with only having 1.5 hours to work on it after work before it gets dark, coupled with it stuck in a creek 80 yards from where I can drive....makes it hard to work on. It seems like something real simple but I have tried everything I know. I found a pin hole leak in the suction side of the primer pump line. However, fuel was dripping (barely) while idling so I wouldn't think it would suck air nor cause the low pressure. I will braze the line then hang a bucket of fuel off the canopy. That is all I have left before I call CAT or you guys give me other ideas. Thanks for all the replies.
I'm thinking something with the pump, might need a reseal or rebuilt
I installed a new transfer pump. Obviously that doesn't mean it couldn't be bad off the shelf. Didn't see anything wrong with the 1st one once I broke it apart and inspected. There isn't much to them. A few seals, two gears, and pressure spring.
I'm thinking injection pump
Where is the "dislike" button! That is not what I want to here.
Just thinking out loud, but primer pump cannot build pressure, when its running there is no pressure, so that's just where I went. Maybe someone with more knowledge will assist.
It is not the injection pump the problem is you are not building pressure it has been a wile since I was into one of those old systems but I believe there is a regulator valve in the pump maybe Nige can help with some info I will research it too where in NC are you
There is a regulator spring in the transfer pump where if the pressure gets too high (about 32psi I think) it will let fuel bypass back around. I haven't checked the one in the new pump, but the old one looked okay considering I didn't check it to specs. I have the book on this machine. Seems like a simple system until the high pressure pump. Guess you just have to know what you are doing. I am right outside Kernersville. The machine is in Stokesdale. I called CAT and they will be out Monday morning. So I have a few days to get this resolved or I have to bite the bullet. I am going back out there tomorrow and on Saturday to scratch my head some more.
when you pump the primer can you hear like a wining or hissing noise from the fuel bypassing
Haven't noticed any noise like that. I did take the primer out to make sure the check balls and springs were fine. Everything looks good.
Any chance that the engine doesnt build up oil pressure in order to release the fuel pump rack?
If have not heard a noise then the regulator has to have trash or is stuck open the hi pressure part has nothing to do with supply pressure go over the supply and supply pump again it has to be there you did clean out the metal fuel bowl at the bottom of the filter housing Right. some models had a fuel l water separator at the back by the tank it is a square glass filter
I thought of that but he said it will run for a minute but would not hurt to see if oil pressure guage goes up wile cranking
Checked with my pump guy he said that the spring and check valve in the transfer pump controls pressure so if you are sure you have a constant flow to the pump it has to be in the check valve
Everything I can find has been cleaned multiple times. I will hang a bucket fuel tomorrow. The pressure relief spring/valve could be bad, but it would have to be bad in the old and new pump. They look good and the spring is stiff. Only way to know if the spring is 100% is to put on bench and check height at different weights. I didn't mention before but I've had a friend look at it. He used to work on over the road CATs years ago. We have separately gone through all of this. We both feel it is a fuel supply issue but can't put our fingers on it. That is why this is so frustrating. Thanks for the replies
No way to put some air pressure back through the line or in the tank ? Also are you certain you don’t have the square glass filter somewhere along the line ?
I bypassed the tank and all supply lines last night when I ran out of a 5 gallon jug. I will raise a 5 gallon bucket tomorrow to see if I can get gravity pressure to help. No glass filter.
Just thinking can you see the end of the transfer pump to see if it is spinning some had a hour meter attach there and you could see it spin also is the mounting gasket in the right position
I noticed the gasket has a right and wrong direction. I removed the hour meter and it is spinning.
Not eddie's problem. But I had this easy fix once. Blew back the line from injector pump to tank. Of course after plenty of head scratching and dead ends. Used a portable air tank.
I doubt this is your problem but loosen your fuel cap on top of the tank to make sure it is venting.
A little off subject. As for venting or maybe not. I Understand that my hydraulic tank needs to build up pressure to work right. So hiss from fuel tank - Bad. Hiss from hydraulic tank - Good.
Yes I took the cap off before. Found a fixed a couple pin holes in one of the primer pump lines. Someone had put some type of tape around it. I noticed it was wet around there, but didn't think it was that big of a deal. I took the tape off and fuel streams out of there. I brazed it at work. I don't think this is the magic bullet but needed fixing. I will put the line back on and hang the bucket tomorrow. I have CAT scheduled at 7:30 monday morning if that don't work.
Cat will probably send someone out who never worked on something that old no place to plug in a computer on that
I talked to the service manager for a while. Explained I didn't want someone that never worked in these. I got "all associates are trained by CAT for all systems". But he did say he has plenty of old timers that work in these all the time. We will see.
Well I hope this service manager is right and he sends someone with at the least grey hair! This sounds like one of those jobs that if anyone of a number of guys here could be there in person it might only take a few minutes to diagnose the problem. It's just that somethings that might jump right out at one in person could take hours of time to type out detailed instructions on what to check only to find out the problem is at the other end of the system! Good luck with the guy on Monday and be sure to let us know everything he does.
I put the fixed primer line on today. Seemed like the pump was a little tighter. I had high hopes, but it was 27 degrees and the batteries didn't want to do much. Brought them home to charge. Carrying 70lb batteries up an 80 yard incline is getting old. I will certainly report back.
Hey Eddie, is this thing running today ??
I was wondering too
Funny thing (not). CAT said tech would start earliest at 7:30 but may have to go to shop first. So at 8:30 I called the office and left a message. At 9 the manager called back. Apparently he called me at my work number to let me know tech was coming. However I explicitly told him to call my cell phone. Since I didn't answer he sent tech to another job and had no one else today. Pretty upset, but rescheduled for tomorrow morning at 7:30. Assured me he would call the correct number in the morning.
Glad to hear it wasn't serious. Best of luck eddie!
I would suggest that you contact your Parts & Service Sales Rep, (PSSR), and let him know what happened. You may be the victim of a more pressing job.
I had a similar experience getting warranty work on my truck. The guy wrote down my cell. number right in front of me to call me when it was complete. He called the home number instead. Told him he called the wrong number when I picked it up. Had to have some more warranty work done and the idiot called the home number again, not once but twice. Worst was the county calling my old phone number from 12 years previous and saying they left me a message. I called that number and the answering machine was a completely different name. Must have been too lazy to look at their updated files for my new number.
I am leaning toward suction side air leak or restricted fitting in bottom of fuel tank. Or, if it is below freezing, ice in the lowest part of the suction/supply line. If a fuel suction line leaks fuel it will also suck air
Update. CAT came out today. I gave him the entire rundown including no pressure at fuel filter housing. He went straight to injector nozzles. Not the direction I was expecting but he is the expert. After some trouble shooting he says nozzles appear to be clogged. Had nozzles brought out and installed. Did NOT help. More troubleshooting and he can't figure it out. Both of us left frustrated but only one of us is going to get a bill. My estimate $225 for truck charge, $135/hour * 7 hours, $240 for nozzles. So $1500 in debt and no closer to getting it running. I'm not messing with it until after the holidays. My stress level is 100% and I want to enjoy Christmas. Will report back if it ever gets fixed.
eddie . i`m sure i`m way off base but has anybody checked to see if the pump is actually in the start run position
It's dumping fuel pressure / flow off I'd start at primer take output line off hand pump. Pump it do u have steady stream of fuel if so cap and make sure hand primer gets hard. work your way to inj. Pump inlet. Snap a few pictures of fuel system I can't picture what system you have some had a bypass valve that needs 25 psi to open that could be stuck open
It has the old fuel system on it it don't have a return to tank. Cat makes no sense the problem is obviously no supply pressure why would they put $1500.00 in injectors in it you can buy these aftermarket for $20.00 each I was afraid you would get someone who don't know old machines
if the system has the constant bleed valve, does it not maintain housing pressure? it may have a piece of crap in it causing it to be stuck open
This system is a scroll with PC. Very simple. I have the book that shows the system. The guy did seem to know a pretty good amount about the system but he did have to make a couple calls. It was getting late, the batteries were about dead and he was digging for answers, so I called it off. The nozzles cost only $60 each, but I estimate the total cost of the service to be $1500 I will have to get back to you guys. I am out of town for Christmas. Thanks for the replies.
check too make sure your rack collar is not stuck in off position ,pull side panel of pump , they may be bypassing , this guy could not get a 955 started the collar was stuck in bypass , after 20 cans of either and burned batteries he walked away and left it there, that was 20 years ago, funny thing, i picked up a 955 20 years ago by just checking the fuel system , was stuck in off position . no fuel too injectors, oh and as far as the cat tech, i had a bad feeling it was going to go that way, didnt get anything accomplished
I don't know about the nozzels, if they did not fix the problem I would tell him to put the old ones back in and figure out what the real problem is! What's the next step in troubleshooting by replacing parts? Is he going to tell you you need a new injection pump? What's next after that, reman engine?
Reviving old thread. I never did get the 955 running. CAT wanted to charge me $1300 for the "non" repair but settled at $800. I asked them what were the next steps in troubleshooting and they said cut the oil filter to see if it had metal shavings. Kinda peed me off since they never verified fuel, charged me $800 then went straight to blown engine. I figured they didn't want to mess with it again. After a few months I had a guy with a big excavator pull the loader of the creek and to the top of the hill. Then I spent about 6 months building a bridge across the creek. Two months ago I found an ol' timer that supposed to be able to fix the loader. He came out to check and the starter wouldn't work. I torn down the starter and the Bendix fork housing was full of mud, not letting the gear to throw out. Fixed that and checked starter on bench. Worked great. Installed starter and it was making a god awful grinding noise. Spent a month scratching my head and checking the starter again. Went out this morning to check dimensions on the flywheel teeth depth, etc. Well, found my problem. I can turn the teeth ring with my fingers. Apparently filling the flywheel housing with mud, trying to start it 1000 times then letting it sit for a year isn't good. SO - still don't have a running loader, and now i have to fix the flywheel before I can get back to troubleshooting the fuel issue. Sorry for the long post, but it has been over a year. BTW- does anyone have tips on repairing the flywheel. Here is a pic of the bridge I built to hopefully prove I'm not a total idiot.
Starter
Fuel system
So is the Ring gear rotating ON the flywheel? If is then it is likely going to need a Flywheel besides a replacement ring gear. Pull coupler to trans, drop all the drive components from rear of engine and full flywheel out, if Ring and Flywheel turn together then may be broken crank.
Yep, I can turn teeth ring with my fingers. Flywheel stays put. I was hoping I could just take out drive coupler for access and not have to pull motor. Put wrench on drive coupler and flywheel and front pulley both turn, so crank is fine. Thanks for the input.
Should clear pulling coupler Ring will be split if that loose
Hey guys - I just realized that I never updated this post. I had to take the engine out to replace the flywheel. I sent the engine to an old timer mechanic to fix a few things and find out why it wouldn't start. He found a bad fuel pump and a few other things. Sent the fuel pump for rebuild and bought some miscellaneous parts including a new flywheel ring. When I got the fuel pump back ($2500) the mechanic started fixing the bad rear main seal and found the the crank was broken. So much for my first foray into heavy equipment. Bought a used engine from local yard and installed. Removed old engine June, 2022. Installed new Nov 2022 New engine has been working great for a couple years.
Any idea how the crank was broken?
Geezers thats a bummer. Did you pump the rebuilt pump on new motor or just going to sell it?
At least found all the problems up front, and the machine IS being used.
Best guess is that the bad rear main seal let in water and mud (remember it was stuck in the creek). Pull the pan and it had what looked like oil mud in it.
I kept the rebuilt pump. The pull out engine works great. Starts in 2 seconds, no ether. I have 60 acres and tons of "projects". Saving pump and old engine just in case
Yep, and with the price of these machines on FB, I am still good if I ever decide to sell.
With the crazy prices of any new equipment I think anything older in semi decent shape has also gone up in value. You want $10K for a 30 year old skid steer? Well, you could buy a new one the same size for $60K+. You can do a lot of repairs for a lot less than $50K.
Have not seen a New decent sized skid steer for less than $120, plus attachments.
I was thinking of a 1300lb. rated machine like. 753 or maybe a little bigger 1845. Haven't paid much attention to new prices since I couldn't afford them. I was shocked at the price of new welders. Unbelievable!