greetings to all forum members. first of all apologize in advance because my language is not English, but have started to work google translator to understand and communicate with you. I recently purchased a 973 serial cat 66g, at first glance the machine does not wear this because I never work with soil or rocks, but work in a warehouse storage of fertilizers. the initial problem of this charger is that it did not move. only 1 meter and stopped. got a manual and started work. adjustments made in linking the servos and many other things. Now the machine if it moves freely. forward back and sides, but after working 10 or 15 minutes the machine stops. enters the vent mode and guess. pulled the lever to park and then restart .and after stepping pedal and steering or try to push the bucket, it stops. I put clocks in the 7 systems. I have given adjustment screw cutting synchronization clockwise to these tests. venturi differential pressure. differential pressure in the filter. underspeed differential pressure valve servo supply. but .... when I test the machine with the clock connected in quick-connect charge pressure of 200psi drops to just under 100 psi which gives way to operate brake vent or spool start spool. that's just some of what I have gathered in this machine. to disarm the main control valve to a piece missing. 1u2604. check valve. the request and I came to miami. the mountain this week and the machine remains the same. not as if this piece he needed. note that this machine was brought from Italy in 1998 and worked until 2009 in many years.And stop there remain several "mechanical" and was not given the revised with failure .. I change oil and filters. first use a SAE 30. I thought the machine to heat lost all the oil viscosity change was equal to 15w40. what I really want to know is where I lost that this charge is for pressure. servo cylinder? Charge Pressure Check Valve? pump varible displacement? no engine tracks. I put a hose in each of them and does not drain oil. any comments that will help me to guide me I will be very grateful.
The problem you are having is when you try to travel the drive loops lose so much of the charge oil that the pressure can not be maintained and the machine vents out stopping the drive. You most likely have a problem in the drive motors. Try to drive in reverse, then try driving one side at a time, both forward and reverse. If you have a 100 psi gauge hook it to the case drain pressure fitting of each motor and try to drive. If you have a bad drive motor the case pressure will go up to 70 psi when driving. A flow meter on the cooler line will tell all about drive loop leakage but you can get by with gauges. Later Bob
Hello Bob. thanks for the interest. last week connects a hose to each track motor. the other two points put them in the cab on an empty 20-liter bucket. Nothing went through those hoses. not a drop of oil. -reverse-steering foward ... nothing. after 15 minutes the machine stopped. only it stops when you strain. Sometimes I stand 2 minutes. I go back to accelerate. and the machine moves and turns hard. this morning I went to make an adjustment to the governor and the valve override. all bad there. I hope that the problem is in that setting. morning after repair parts. start again and prove that happens. I see so many people worked on this machine without knowing. and they have managed to get out of control the entire system. I think all the relief valves have been moved. hopefully not. I would like to send photos or videos to the forum. Might video on a failure to appreciate better presented. tomorrow I mention what happened to the governor and setting override.
What's up friends. Yesterday I finally turn on the machine. I made an adjustment to the governor linkage. underspeed also override the valve. working around 20 minutes without problems. then stopped 5 minutes. I went back to accelerate and try to turn the machine and vent again. However. if we speak of a load pressure drop. where to start looking? and will comment on the hoses that connect to the track motors. not pour oil. could disarm the main control valve. Charge pressure check valve? or you may have a cylinder leak? I also read that there is a check valve vent within charge valve.suppose you have a leak in the variable displacement pump. I do testing? as if the leak is there? .... or perhaps one of the relief valves defective or wrongly calibrated? I want to start on Monday, removing the main control valve and review the charge pressure check valve. but any ideas you can give me is very useful .. greetings
Don't take anything apart until you do a complete pressure test and know what to fix. If you take it apart first you will complicate things for yourself. Get the pressures across the front of valve. Upstream, venture and servo supply and the charge, near steering levers and brake on top. The LH drive is on the valve body and the RH drive is on a block very low near the back of fuel tank. A low pressure gauge in each drive motor will tell condition. A flow meter on the cooler line would help but charge pressure will tell a lot. Lock the brakes by removing and plugging the release line. Leave end towards the brakes open to air. Check the brakes will hold then heat up oil and check pressures at full stall forward and reverse. Maybe someone can post the test sheet for you. Later Bob
I try to put the pictures of the pressure tapping points
ok here we go. 1. Pressure tap for underspeed pressure valve throat. 2. Pressure tap valve upstream pressure for underspeed. 3. Pressure tap for brake pressure. 4. Servo supply pressure. 5. Venturi throat pressure. 6. Venturi upstream pressure. 7. Charge pump pressure (filter relief valve). 8. Charge pressure 9. Right side drive pressure (forward & reverse). 10. Left side drive pressure (forward & reverse). I have no flow meter. I have only indicators. from 60 psi to 5000 psi.It is that in points 9 and 10 exceeds 5000 psi. as did those tests. You tell me which points to begin Monday. the other photographs are of the machine today. hood side panels. and protectors below are saved.
You need to check pressure at 3 4 5 6 8 9 & 10. You can take the brake release hose off or the valve and cap the fitting to load the drive for testing. Test complete system as it is, then test with RH and the LH pedals half way down so you can see how it drives on each side. This will show if one side is bad only, then I take the drive hoses to the motors off and plug them, run the test again and see if the problem is in the pumps or motors. Later Bob
OK. First. Let me see if I understood. you want me to take the pressures at points 3 4 5 6 8 9 & 10. This will I do when the oil has the normal operating temperature. (I close the synch shutoff valve for this test ???) or (I condemn "close" the hose releases the brakes ???) the black hose that is in the hands of the Lord. you want the closure for testing? if you shut the machine will not move. The tests conducted are made with the parked machine?
Yes check and record the pressures at the points I mentioned. Lock breaks and make sure they will hold the machine parked at full power. Pressure readings are taken with machine parked. The sync shut off can remain open for this test, it is closed to adjust the machine travel straight when finished. Forgot to mention to put a tach on the engine for this test. Load the drive and watch the gauges, pull as far as you can without the drive venting out, then back off, do a few times in forward, then a few times in reverse. Observe gauges and record readings. Try to get to full travel if you can. If you have vent out then try again but with one steering pedal half way down to get ZERO drive pressure on one side, compare charge pressure when loading half system and full system. Repeat with other side at ZERO drive pressure and again compare charge pressure to the pressures read with other tests. Do these tests and post results. Later Bob
OK. then in points 9 and 10 I put indicators 5000psi. put the governor in high idle. and pull the lever foward and reverse. without placing the brake hose. then foward and I pressed the pedal steering. a side. then the other. just in reverse. Indicators should then get to 0 ... or what would be the expected result in this test?
You can zero out one side at a time in forward and reverse. By doing this you only load one side at a time and if one side is bad and the other good you will see the drive not vent out when driving the good side. If they are both just worn and leaking a bit they may not vent out driving one side. We will see. This effectively tests each side on it's own. You know condition of RH and LH. To test deeper take off the main drive hoses and plug them, repeat the tests and you now know the condition of each pump and motor. Watch charge pressure as you test. It will raise and fall as cooler flow does. Cooler flow indicates drive loop leakage. Later Bob
a greeting friend bob. Today I started testing ... I began to block out the brake. and place the hose in points 9 and 10. and the track motors. at first when the oil is cold the indicator exceeded 5000 psi. Here the images.
after moving fwd and rev lever several times at intervals of 30 seconds ... the machine began to vent. I guess you meant to do these tests. Note that I have no tachometer. So I put it in high idle. flowmeter have not ok. only indicators. with the lever in park and high idle 230psi 230psi lh rh ... then take 2000psi and was reduced to take one of the two to 500psi. both they stopped at 500psi. no pressure differences.but......
pressures made today are not equal to the comparison table .. I track of motors nothing came of oil. the right leaving a drop every ten seconds. in all ranges of acceleration and movement of the lever fwd and reverse .. another thing I noticed was that before starting the machine oil in the transmission was in the middle level between add and full. start and after more than an hour and turned the brand is in full. should not be the other way around? if the cooler is higher than the transmission should level off at. I did not upload it. do you think there is any restriction ??? another thing I saw when the idling high and lever in the park. the left pedal pressed and held in 230psi but when I press the right pedal pressure in the pump up to 420 psi. you may just need adjustment? That's what I saw damaged. apart from all the pressures that are wrong. Hahaha. remember that synch cutting screw is open. I always did the tests with closed screw. you tell me where do we start .. or maybe sell it for parts lol. joke.
Could you try another gauge on the servo supply tap, something is wrong, servo pressure must drop over it's valve to charge pressure. Servo must be more than charge/brake pressure. Are you sure the hose ends are open on the case drain fittings. Something is not right there. Later Bob
Hello Friend. I am going to change the meter. and change the hoses on the track motors. but I have a suspicion that this defective one cylindro. not you think? mind you. the drive pressure to reach 4500 psi in fwd lever and then vent. but when the lever is in rev only reaches 3500psi and vent the left side. 4300psi for the right side in rev. should vent in the same psi both fwd and rev ??? That could explain why once the machine is start the oil level in the transmission goes up instead of down ??? or maybe I'm wrong? is there any test that he can do to cylinders?
The HPCU shouldn't vent out, this is caused by low charge pressure. Low charge pressure is a result of drive loop leakage. I suspect you only need the drive motors rebuilt but need to be sure. Try to get plugs for the drive lines to block off the HPCU outlets and test again as you have but without the motors. A big improvement would say motors are problem. Later Bob
I'm wondering how you have no case drain at all. I've never seen one of these machines without a little case drain. Are you sure you did the test right or did I miss something else that has shown actual case drain.
I changed the hoses and oil pressure came not there. drops only. place a direct indicator. and I do not get the needle. I suppose you want me to close the HPCU outputs. you want me to block these ??? both sides? or one side at a time? I lock the small hose down too? or is it just the greatest? (thick)... Today I returned to position the pointer in making the servo supply pressure. in this indicator she had a pressure drop of 340 psi to 140 psi .. it is normal to lower the pressure in the servo by the load pressure drop? another question. You have no idea of the cost to repair one of these bombs? Thank you. later
Hello. only when I remove the original cap to place the hose or tube. then pour a little oil. but it is not pressurized oil.
Something is very strange with the case drain, it should pour oil out under load. Servo supply pressure shouldn't drop like that either but the charge should. Yes I would like you to block the 4 drive lines and test as you did before. Compare all pressures and if you can load it up and not vent out. Later Bob
bob friend. sorry for the delay. I was doing pieces to close the hoses. I've done what you told me. I closed the four outputs of the hpcu .. nothing. returned to vent. I guess we are not the track motors? so. who do you think? Damaged pumps are variable displacement? or are there other tests be done? Thank you
You have eliminated the motors, looks like the pumps but there is one more place to check. The aluminium plate between the valve and the HPCU case. Change that. I have seen them leak charge pressure and cause vent out on a good system. Cheap to try. Later Bob
you think this broken aluminum? o-rings or damaged? we can achieve in this case. in this test? pressures to communicate? between the aluminum plate and the main control valve (not leak out. This dry. also recalls the low pressure servos. 340 drops to 140 psi. and vent. on Monday disarmed the main control valve. Also plate. and overspeed valve. I will review everything. thank bob.
It's the aluminium plate between the HPCU case and the valve body with the test fittings on it. They start to leak over time and will cause vent out with an otherwise good system. Later Bob
BAD NEWS. how are you bob. this day I set out to take the aluminum plate as we agreed .. first drain all the oil from the transmission. then remove the main control valve. but. when remove the top cover to clear the valve pilot to also take the aluminum plate. surprise !!!! I discovered bronze chips at the corners of the servos. I've taken many times the upper deck and had never seen bronze chips or splinters. this has happened then close the four hoses to the motors track. you believe that is the product of it? or that the bomb was almost bad and not take the test? anyway. anyway if they were not bad now if you are. I guess that comes from bronze plate of the pump or sneakers. I think this repair will take longer than expected. if the dishes are scratched pistons and barrel .. we are talking about much cost.? what do you think. ? I do not want to disarm the hpcu not keep spares. I do not want to disarm and then remain so for months.
You have a big problem with wear in the HPCU, likely the port plate. Keep the machine together so you can move it on to a float for a repair. You have a big job to do, very expensive but do it right or it will cost you a lot more and the machine will never work right either. Hpcu and motors will need rebuilding, all lines and the cooler will need cleaning out. Later Bob
I have just read this thread from the start even though the machine and it's problems are way beyond my level of intelligence!!. I an impressed with the trouble and time that both parties from opposite ends of the language barrier have overcome to try and get this machine mobile again.Fair play to Mecaniquin for trying to translate and fair play to Bob for trying to fathom out the problem and the language.I am sure that between you all,you will get it going. Good on you
what I do not understand is that ever after 4 months of testing the hpcu never showed chips inside. repeatedly drain the oil from the transmission and never had chips. after the test that closed the passage of oil to the track motors it was why this happened. you think and bombs were scratched and worsened in the test? but nevertheless I want to thank you for guiding me in the development of these. Perhaps soon disassemble hpcu to see the damage and follow the thread of this conversation.
Mecaniquin, Don't take the HPCU and Motors apart unless you have a well equipped shop to work in. Beware of the drive motors, they have big springs inside that need a tool to hold for removal. I tried to take one apart once and the spring got loose, shot out, took my glasses off my face, breaking one lens and pulverizing the other into sand. "Also be careful of any discount rebuilt units or "surplus stock" They might be junk. It's an expensive repair to do right but a lot more expensive if you don't do it right first. Good Luck. Later Bob
okbob. Thanks for councils. a question. because I must repair the motors track if these are supposedly good? we stayed with the evidence that they have no escape. Chips not reached them. hoses were blocked .. I thought it only was to repair the hpcu .. change the pistons, plates and if necessary the barrel. something like the work done by a user named cmark I think a cat 953.
I've been watching this thread for a while and I have a suggestion/thought/question regarding the motors. Are you absolutely 100% sure that NO contamination at all has reached the motors..? I understand that it might not be very likely, but if there is even a small amount of contamination in one or both of the motors then it is possible that it will get back to the HPCU when it is all reassembled and operated. That could cause a new failure.
We did actually strip/clean/inspect the motors on that job. Although I didn't show pictures, it is mentioned in one of the posts. In my opinion, if you are going to spend multiple thousands of dollars on overhauling the HPCU, you should at least open up and clean out the motors if only for peace of mind. Also consider that when the HPCU is removed, the motors are much easier to remove.
I assume that because the OP is in Venezuela his language is Spanish. I speak Spanish so if there are any translation issues that need resolving then post something in Spanish or email it to me and I'll translate the text into English.
Hello friends. I hope all are well. I am writing to tell you that two weeks ago to take the transmission and disarmament looking for faults. about 1/2 tool ... I was in the variable displacement pumps. fortunately did not explode the housing of hpcu .. try to do everything possible to work cmark, but is unsurpassed ... start the machine. and this as before. the same fault. only now no keys inside.
the key is housed in the rear of the pump. then run to the pistons. do not know how someone will drop a key. guess they were his previous mechanical .. the question is already built it. and still it has the initial failure. but there is more. !!!!
okay. I step back in time. a year ago when the purchase disassemble the transmission. it was first remove the oil pan. and got this ..... I call this number fails 1 .. 1/4 tool in the oil pan. and capping suction tube. I figured that was the fault because I thought that the charge pump did not have to carry. remove the key. wash the tube and place again.
recalls that at first the machine would not move. ? I made an adjustment linkage and now that it moves freely. call this number 2 fails .. then the vent machine. not knowing where to look and disarming some things come up. two speed valve engine. I think it's called. one of the four pistons was replaced by one made by hand I think. set photography. this is the fault 3 .. I went to the caterpillar supplier in the area. and he told me that this piece is discontinued. so it sends to do better with mechanizer. (Turner) not with a file by God.
then keep looking and reading the manual. absolutely knew nothing of this machine out of your engine until one day I discovered it was missing a valve in the main control valve. wait a month to arrive. I was sure that was the fault. finally I arrived. and nothing. this is the number Wrong 4
after that I communicate with you. where I learned a lot about the functioning of these hydrostatic. and what happened wrench 1/2. this is the fault .. number five. when I was hpcu disarmament disarming the main control valve. In its whole. with the book in hand. I got the quick response valve is stuck or jammed. so much so that to loosen use a hammer and a small steel bar. fault number 6
also remove the main valve. and got this. I think is important. fault number 7
Tuesday hpcu place the machine in the starting Wednesday. and still has the same fault of hell. ah but no more. there is a screw which is called .. underspeed cut-in adjustment screw. because this screw never wanted to move because I figured he had a factory setting. yesterday decided to move it. and it turns out it was turned all right. abutted against the valve that moves in there. that certainly is number 8. fails both so not turned with a screwdriver. I had to remove it completely, and turn by hand. 15 laps gave him backward. trying at every turn. and nothing. I need now is a tool according to the manual to adjust this valve with overspeed. underspeed cut-in tool (I think it's also the thing).
okay. thinking a little about what happened to that machine, thinking a bit like csi lol I think the former owner at some point the fault is present in the o-ring broken or quick response valve or blocked suction. some people without knowledge tried to fix the hpcu and left two keys inside and all relief valves or other and linkage misplaced. I'm sure the friend bob I will say that the bombs. lol but not because I think this machine is now out of tune. or what you call the loops of the unit. there any way to adjust the underspeed or overspeed valve and screw cutting? I think it's my last hope. if not that then I will have to buy someday become a hpcu repowered. thanks guys. Goodnight.
In your post #43, the first picture is of the overspeed adjustment. The second picture is the underspeed adjustment. The underspeed screw is the important one and yes, you need the tool and an accurate tachometer to set it. Were the faces of the barrels and port plates in good condition?
yes cmark. a barrel was not damaged. and bronze dishes were good. not scratch. the tool stay behind the piece that oscillates. (which carries the two large bearings) against the wall of the housing ... Too bad we did not take photos. I had thought that there was a method to adjust these valves (without the use of these tools) then I will have to wait for one of these tools. I doubt that today's selling. another thing. in principle 30. use an oil after use a thicker 15W40. I now understand that this affects the differential pressure across the filter discharge valve. in a tropical country that oil recommend? TDTO here the cat does not exist.
According to the OMM, 15W-40 is good for an ambient of -15 to +50°C. Did you check the port plates and head for flatness? If there is any problem here you can get what's known as port plate separation which will make you lose charge pressure. (By the way, the name of the oscillating part is "swash plate")
bronze dishes that go in the pump head were perfect. and a barrel mark very, very thin. not even you could feel with your finger. I have taken piston pumps excavators and backhoes that are horrible and still work. I will confess that I am not an expert, but if you differentiate between good or bad. the case is that no pressure is set to manual. upstream of venturi 500 psi. 320psi throat. Charge pressure 210 psi. 280. servo supply and are all well. wrong. venturi should be 450, 230 for a differential pressure of 180 as the book says. servo supply 350. No 280. pressure filter 550. The differential pressure between filter and upstream of the venturi should be 25 psi. if I can lower the pressure in the upstream of the venturi 450 would be worse the differential with respect to the filter. would have 150 psi differential. all measured with full rpm hot oil. also do not know if this is something wrong under the top cover, because it fails to reach the neutral hydraulic servo valve adjustment. and I did go above several times. the manual says that with the lever in neutral to full rpm 200 + 40-15.because by making the hydraulic adjustment watches erratic shown. the pressures oscillate strangely when I turn on one side and the other not. this is crazy friend. in the weeks to change the oil less viscous one and try to bring pressure to their standard measures. starting with the filter doing all the way to the end. shame it takes the cutting tool underspeed. I find it hard to get up. It is only for these machines.
If I understand you correctly, you have 500psi venturi upstream and 320psi venturi throat giving you a delta of 180psi which is correct. Charge pressure of 210psi is also correct. Servo supply pressure of 280psi is wrong. If you move the FNR to the brakes off position (which is the point where the underspeed valve raises but the pumps are not stroked) what are your charge pressure and brake pressures now? Have you looked at media number RENR3686 in SIS? It takes you step by step through the various pressure tests. If you are working from a paper manual, you should find it in the Troubleshooting section.
I have no cmark book. everything I see by the sis. It says 450,230 for the venturi. not 500psi. the differential pressure across the filter should not exceed 25 psi over upstream venturi. therefore he asked about the oil. in the sis it says that if the pressure differential is greater must be the oil outside temperature highly viscous or obstructed filter. I change the filter and install a new one 1r0741. anyway I'll try to change the oil and put a sae 30 and then pressure testing again and tell him how I was. I will also look at the renr3686 thanks cmark
Are you getting confused with "charge pump pressure" and "charge pressure", they are not the same thing. Following the logical flow of oil from the charge pump, the first pressure reading should be (1)charge pump pressure, next (2)venturi upstream pressure, next (3)venturi throat pressure, next (4)charge pressure. If your delta between (1) and (2) is >25psi then you have either wrong oil, blocked filter or faulty filter relief valve. If your delta between (2) and (3) is <160psi then you have low oil flow meaning worn charge pump or low engine speed.
I understand mark. I'm not mistaking. the charge pump is the small gear that goes in the front of the hpcu and measured at point 7. load pressure is another and goes on to point 8. So we're good. what I mean is that in the sis says the venturi upstream raises a pressure of 450 psi at full rpm and my reading gives me 500 psi. sometimes 520 psi. and throat rather than as sis says 230 psi. I 320 psi or 350 psi. although its pressure differential pressure is within the rules, they are still high .... I have seen how the valve underspeed going up. as raise the engine rpm with the brake lever off ... but abuts the valve (above) when the 1800 rpm for approx. I can accelerate more. but the valve and this butt . as if there is a lot of pressure and the engine is not yet a full rpms. let me change the oil. and bring a thermometer. for testing properly. I think oil is not correct and relief valves are out of range. I'm getting more and more convinced that this machine was sabotaged.
I think you're right, I've been following the thread and don't see how some wrenches were accidentally left in the system when everything has to be adjusted so closely. I keep a mental inventory of tools when I'm finishing up with something like this.
hello cmark. a question. you know your tool (underspeed cut-in tool group) have by chance a photograph of her? any specification? you know if she wears in a spring? try to make a similar. and I could adjust the valves. but not if they are set correctly. in the manual it says to tighten the screw 121 mm approx. take into account the height of the bracket with height of the upper deck. and fails to make contact with the valve underspeed. contact can do 136 mm approx. I got a tachometer and achieve adjust the overspeed valve. so: 2125 rpm to 2340 rpm (hi idle) light comes on. when decreasing rpm less than 2125 rpm the light goes out. adjusting the valve to the left. also did the same for Underspeed CUT-IN ADJUSTMENT SCREW. but adjusting to the right. in order as the manual says. I do not understand is that if the bracket has the height of the cover, adjusting screw 121mm not making contact. however the spring is pushing all the way up. I just want to know if I was wrong in some detail of the tool. Here some photos
No problem. Here is what you need. As you can see from the second photo, the end of the contact is almost exactly flush with the bottom of the feet. I've never had to adjust it more than 1mm each way from the current setting. The procedure is (briefly) 1. Wear some earplugs! 2. Set the engine RPM to the specified high idle. 3. Very carefully move the FNR control on the transmission until the underspeed valve raises to the top but the pumps don't come under load. That is what the homemade adjusting too on the left is for. It is too difficult to maintain the correct position of the FNR lever by hand. 4. At this point the contact tip on the tool should be just touching the shoulder on the valve and the test lamp just lights. Adjust it until it is. 5. Slowly lower the RPM until the test lamp just goes out. Adjust the underspeed screw until the lamp goes out at the specified RPM. If I understand you correctly, you are doing this but the underspeed valve is raising high enough, correct? If so then you possibly don't have enough delta between your upstream and throat pressures to compress the spring.
cmark thanks. that if the original part. last week I was bored and manufacture a homemade tool. I know that the screw from the big nut to the tip must be set to 121 mm. Now the height of the bracket obtained from the top cover. I just want to know whether the measures are the same as yours. my height is 136 mm bracket. that height is yours? I guess its original tool takes an internal insulator. place a 12v battery near the hpcu. the negative pole to the hpcu. positive to the bulb. an electrode through the tool. Insulating a straw. (cigarette) (plastic). and works. the valve completely underspeed spend up to 2125 rpm. the light turns from there to full rpm (2340 rpm approx) but if my bracket is high, I will get an erroneous measurement. I think. Here a picture. otherwise, the measurements made with the hot oil. but even still it is falling load pressure. 200 psi falls below 80 psi. applies the brakes vent .. you believe that the adjustment of these valves has something to do with the load pressure drop? or I'm just plowing the sea? cmark thanks again.
Here is the measurement (Photo1) but if you're making your own tool, the dimension doesn't really matter. What you need to know is that the tip is flush with the feet. (Photo 2)
cmark ok. I will keep it in mind. I ask the question again. you think the load pressure drop is by improper adjustment of this valve? or they have nothing to do with the low pressure load?
I think we are losing something in the translation here. By the way, I think you are doing a good job in communicating a technical subject in a language that isn't your first language. If I understand you correctly, you are asking "can an incorrectly set underspeed adjustment screw cause the system to vent?" My answer is No, (although others may have a different opinion); I have never experienced a situation where a maladjusted underspeed adjustment screw causes anything other than low torque to the travel motors or engine lugging.
cmark exact. that's what I ask. Speaking of motor overload. Right. when I power the pumps. the motor is overloaded before vent. it stalls. in order cmark. thanks again. I'm not a mechanic by profession. what little I know I owe to my father that if he was a good mechanic. I helped priate was a boy. you have helped me a lot and I thank you. I think at the end I will buy 18 barrels pistons and polish., yesterday talking to some mechanical caterpillar gave me a phone number of someone who apparently knows these hpcu. these machines are not common in my country. after a few days perhaps come and check the transmission. I just want to know exactly what to buy. although I'm not afraid of that transmission. if I have to remove it ten times, I do. just I do not want to make spending pistons or barrels. and then it appears that the adjustment was missing. Do you get me? again thank you and all the good will, and depending on what you tell me the mechanic informs me back with you. My regards, brother.
You also need to be sure that your problem isn't caused by low power from the engine.
Hello everyone. A pleasure to greet I wanted to tell you that a few days ago I resumed work on 973 ... I got in the main valve body that its springs had been changed. One is longer than the other. So look for the specs in sis. Spring 5 was replaced by 6. changed place And to change them there was no more ventilation .. Also repair a chain .. and take a brush and some paint. Also install new board with mechanical watches. And I've adjusted the muffler. Now it looks more like a machine. but.......
Some of the work in the chain. Change of seal .. that supports the fat. And filling
And some paint internal results
okay. Now my question With the change of the springs in the main valve body, and the machine has not re-ventilated. But here is the doubt. Now the fault has mutated. It turns out that after doing an open field test, the machine rotates perfectly. And has strength that slides the chains against the earth .. but after five minutes .... (oscillates) or comes and goes. hard. And without force. The oscillating plates come in and out. Without my permission. Lower the load pressure. But it goes up again. And thus has mutated the fault. Within what little I know, my opinion is that an adjustment is missing. (I do not know) I think that if the piston pump had excessive leaks, it would not oscillate? or if? Cmark. ... or whoever may be interested, here is a link on YouTube for you to see the flaw. Note that the charge pressure gauge is below the large one. To your left down supply to the servo. Above the supply this upstream venturi. And to the right of the great meter is this brake pressure. Drops like the load pressure ... this is the link ( )
OK. I'm guided by sis now. Tests and adjustments. Will make this section in the test .. Test 13.Make sure center pedal adjustment is correct. The bolt must go through the hole in the lever into the threaded hole in the valve. In the BRAKES OFF position, check the pressure to the top left plug in the main control valve. A. If the pressure is greater than 860 kPa (125 psi), check for debris blocking the operate / brake spool. B. If the pressure is less than 860 kPa (125 psi), from the following. * Back flush hole. (See LOADER WILL NOT MOVE; PLUGGED ORIFICE IN MAIN CONTROL VALVE CAN BE BACK-FLUSHED in the Troubleshooting and Service Tips section of this publication.) * If this does not solve the problem, of Test 14 .. I do this test. And in the left cap I have a pressure of 250 psi .. and charge pressure around 220.psi. answer: A. If the pressure is greater than 860 kPa (125 psi), check for debris blocking the operate / brake spool. I remove the spool in the main control valve without removing the body. And I get this. speed-brake control stem Has been hit twice. I guess in an attempt to move her back. Maybe they thought she was stuck and beat her with an iron. Now my question for you is. Does that hole drain oil? Because when blowing with my mouth does not enter or leave air. Is covered The blows have deformed it internally. Since it is as fine as a needle. I ask this question because in the hydraulic scheme does not seem to play a role there. I watched. another thing. In the diagram there is talk of a hole 54. That hole is the one that is hit. ? Or speak of the hole start vent spool left? read this paragraph. As before, the oil from the servo relief valve is sent through external line (51) to replenish the drive circuits. The oil is also sent through charge pressure check valve (24), past the operate/brake spool and start/vent spool, to the pilot valve. When pilot valve spool (55) was in PARK, charge pressure oil was directed back to the start/brake spool to fill the chamber at the right end. The pressure in the chamber caused the start/brake spool to move to the left (position shown). With the start/vent spool in this position, the supply of charge pressure oil from the charge check valve is now sent back to the operate/brake spool where the flow divides. Part of the oil goes through tube (52) to reset the drive loops. The remainder goes through orifice (54) to the chamber at the left end of operate/brake spool (21) and to a chamber in pilot valve (5). When the pilot spool was in PARK, the chamber in the pilot valve was open to tank. This prevented the pressure from increasing in the chamber at the left end of the operate/brake spool. When the pilot spool is moved to BRAKES OFF (in either forward or reverse), the tank passage in the pilot valve is blocked. The pressure in the chamber at the left end of the operate/brake spool will now increase, causing the spool to move to the right. The spool will move until it makes contact with the end cover on the valve body (position shown). The spool is now in a position to send pressure oil through the brake line and to block the flow of upstream oil from the quick-response valve to the top of the underspeed valve, the chamber around the quick-response spool, the underspeed override valve and the spring chamber of the overspeed valve.
This is start vent spool. Has a concave hole. And if it is free. You can look the other way. so. I want to simplify my question. The hole that is hit in the spool speed-brake drains oil or not? I do not know if I should drill there or not? I do not know if it's really a hole or a plug? Or acts as security, and opens to a certain amount of pressure. I do not want to hurt more than it already is. In the part book I could not even find their number (code) to know if they sell it or not. Thank you and happy night
Hello friend, greetings. I need the google translator again to communicate with you. I write to you after so long for two reasons. the first is that I wanted to thank you again for your support, all the knowledge acquired here is priceless. in thread 45 and 47 cmark explains about the separation of the pressure plates in the axial pumps. The mistake was mine because although I did not find scratches, there was certainly separation between the barrel and the bronze plate, therefore the loss of pressure of charge, I understood that after talking with some good people who repair hydraulic pumps. I bought new pistons and the faces of the barrels were flattened by them. so I wanted you to know that the big fault was by plate separation. I made some videos that I wanted to show later so that they could appreciate the behavior of it after the assembly. I was running to the side and made an adjustment on the synchronization valves and I was straight. I worked for about 5 hours and the machine did not enter the ventilation mode.
very good. However, when this machine does not bite, it kicks ... after these tests I could see that I had an oil canister for the final drive. The import duo cone seals were ordered, while waiting for them the machine did not turn on for about 20 to 30 days. Then when I turned it on, the machine did not move quickly. At first glance, I thought I needed an adjustment in the sub-speed shut-off valve. Install bulb tool, turn screw, and sub-speed valve back up and again wide movement in servo valves. Bravo ... I felt an expert in hydrostatic. Lower the radiator for internal washing. oil filter change, and some beautification in the cabin, lights, alternator, new teeth for the shovel etc ... and the machine would be inactive again a month. then it would not move again. It ran faster when the idle slowed down. completely remove the sub-speed shut-off valve and the internal reel was clogged. disassemble the main control use paste to grind valves. install, the machine remains the same. I'm going to the most technical part. pressure test. venturi differential. and throws me a differential of 20 psi ... at low and high engine rpm. I follow the instructions in the manual, I make a venturi pressure differential upstream minus the load pump, this test gives me a pressure differential of 20 psi.
I made some adjustments to the sub-speed and overspeed valve and now it doesn't even move. The sub-speed valve still does not appear up. take brake pressure out of curiosity and when moving lever f. p. r. towards the brakes without position, it goes from 0 to 200 as in thirty seconds, it takes a long time for the braking pressure to appear. Yesterday I decided to follow the manual and check the external line of the charge pump, good seals. dismantling main control, filter bypass valve was checked. the filter. quick response valve. Orings Venturi. internal springs reels The charge pump was checked in a test bed early today with positive and negative suction. They told me it was good. I put it back together I turned on at 3 pm. and follow the sub speed valve without appearing above. The only thing I didn't check was the internal suction tube of the transmission, the one with the screen. the manual tells me that if there is no differential pressure in the venturi, the problem must be upstream, bone, towards the suction. It is what I understand. If someone can give me a ray of light I would appreciate it. P.d. When I write underspeed and translator place sub speed. I think they understand me the same.
How are you guys doing? I wanted to inform you that after reading the manual for a while, it occurred to me to change the filter to the hpcu. I had a 1r0741 filter on, replace it with a donaldson p556064. I had not changed it before because as I said before, the machine worked at the beginning with 15w40 mobil and a 1r0741 filter. I want to change the oil to a sae 30. Here it has the name of agrofluid. If I do not remember I think that caterpillar asks for an oil that meets the to-2 specifications. around here they sell a tek star brand oil. The model is JD-20MP tractor fluid. UTTO . says it exceeds the caterpillar to-2 specifications and others. In conclusion, I wanted to report that the problem was already resolved. I guess there was not enough flow to the venturi. That's why I want to add a less viscous oil. If you can comment on what oil to add, I would appreciate it. I already commented in another thread that the caterpillar tdto does not exist. there are also some oils here, super s 303. cam2 303. mobil fluid 424. castrol AGROF. Your opinions with these brands would be appreciated.
Cmark is the hydrostatic loader expert but I'm going to jump in here with a couple of comments that came up recently regarding another hydrostatic loader. HeavyEquipmentForums 1. The 1R-0741 filter Part Number is incorrect. You should be using an Ultra-High Efficiency element Part Number 132-8876, or Donaldson Part Number P165239. The use of the UHE filter is critical for correct operation of the hydrostat. https://shop.donaldson.com/store/en...iginalSearchTerm=132-8876*&_requestid=6952509 2. The oil that you should use in the hydrostat system is nothing more than a Hydraulic Oil of SAE10W viscosity. This will cover operation in an ambient temperature range from -20C to +50C. See below. The SAE30 oil that you propose is far too heavy a viscosity, even in your climate. If it is available something like Mobil DTE10 or DTE20 oil in ISO46 viscosity rating would work fine. If you ever have problems with posting in English then please post in Spanish and I can translate it. I speak Spanish - I have to as my wife is from Colombia....!!
I can't speak Spanish,but I'm pretty good at double Dutch in the pub
I speak fluent drunkenese in 16 languages......
Jajaja borracho muchos hablan en ese idioma. esta bien nige, entonces me haces dos sugerencias. La primera el filtro, creo que es fácil conseguirlo. Y la segunda es el aceite, el cual no veo tan fácil. Sin embargo trataré de conseguirlo y enviaré un video donde puedan observar la máquina en funcionamiento. En la tercera página de este hilo cmark comentó que si podía usar 15w40. Hago incapie aquí. No es que no quiera usar un aceite 10w es que simplemente no existe aquí. No hay mucha variedad y menos con los problemas que se viven aquí. De todas maneras trataré de conseguirlo. Esperemos también a ver que nos dice cmark. Les informaré como me fue. Gracias por responder nige. A todos gracias...
And translated that says - "Ha ha, drunkenese, lot's of people speak that language. OK Nige, so you are making 2 suggestions. The first is the filter which I believe is easy to get hold of. The second is the oil, which I don't see as being so easy. However I will try to get hold of it and I will post a video of the machine working. In the 3rd page of this thread Cmark commented that 15W/40 could be used. I failed to find it here [I'm assuming this refers to the 10W HYDO]. It's not that I don't want to us the 10W oil it's simply that it's not available here. There is not much choice, and now even less choice with the problems of living here. Notwithstanding I will make an effort to find it. We'll also see what Cmark has to say on the subject. I'll keep you posted how it goes. Thanks for responding Nige, and thanks to everyone." OK, I will admit that I missed CMark's comment about using 15W40 on Page 3. From the extract of the Manual I posted above 15W40 does not appear in the recommended lubricants for the hydrotat, all it mentions is hydraulic oil of various viscosities. Una consulta a mecaniquin. Puedes conseguir un aceite hidraulico de viscosidad ISO46..? Eso funcionaria.
Very true. I admit I was surprised myself but it's the closest the OMM gets to mentioning the hystat so what can you say? If it were mine I would be putting hydraulic oil in the tranny but we can't escape that fact that it will run on 15/40. There's a video to prove it.
I guess the $64,000 question is “will it run any better on a 10W or ISO46 hydraulic oil which would be of a viscosity at 100DegC around half that of the engine oil.?”
Ok muchachos. Nige, gracias por la traducción, no quería hacerlo antes porque recuerdo haber leído en el reglamento que el idioma era inglés. Entonces tú dices iso 46. Es bastante delgado ese aceite. Y bueno el 15w-40 como dice C mark, funcionó. Pero quizás obstruye el filtro después de cierto tiempo de trabajo. Por eso voy a buscar el filtro de ultra alta eficiencia y buscar el iso 46. Si no lo consigo, trataré de usar un aceite que cumpla o supere los requisitos caterpillar to-2. De todas maneras aquí el aceite no se pierde, si no funciona, se lo agregamos a las otras maquinas viejas en los hidráulicos. Les mantendré informados.
Mire, el manual indique que un aceite hidraulico 10W (o ISO 32/46, son lo mismo) es recomendado para un rango de temperatura ambiente entre -20 hasta +50 Centigrado. La viscosidad de un ISO46 es un poco mas pesado de un aceite motor SAE15W. Vea grafico abajo. De hecho el equivalente exacto a un SAE10W es entre un ISO22 y un ISO32. En numeros redondos digamos un ISO32. Pensando en la temperatura ambiente donde estas tu cuando sugiero un ISO46. The manual states that an SAE10W (or ISO 32/46) hydraulic is recommended for an ambient temperature range covering -20C to +50C. The viscosity of an ISO46 is slightly heavier than an SAE15W engine oil. Actually the equivalent of an SAE10W is in between an ISO22 & an ISO32, call it ISO32 in round numbers. I was thinking of your ambient temperature when I suggested an ISO46.
por aqui estoy viendo un aceite marca super s aw46 hydraulic oil. tambien hay uno marca dauer hplus premium hydraulic oil aw46. cual crees que sea mejor?
He's asking about 2 locally-available brands of ISO46 hydraulic oil. One I can't find any information on apart from on Mercado Libre which is the Latin American version of Amazon. I'm not so keen on that. According to the Datasheet the Super S AW46 is formulated to meet the following specifications: - Sperry Vickers M-2950-S & I-286-S, Denison HF-0, HF-1 & HF-2, Cincinnati Milacron P-68, P-69 & P-70. I would go with that one.
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Hola muchachos un saludo a todos. Disculpen que les escriba en español, estoy seguro que nige les traducirá al inglés para un mayor entendimiento. he estado perdido estos meses. Ocupado en otras cosas. También por el tema de la pandemia las cosas están un poco paralizadas. Hemos hecho algunas mejoras estéticas. Tenía 7 dientes con bases me falta comprar un solo juego. Hice algunas pruebas en mayo pero el motor tendía a recalentar. He sacado el radiador han limpiado y ahora esta mejor. Esta semana la he puesto en marcha y he trabajado alrededor de 4 horas y corrió bastante bien. Quería saludarlos y mantenerlos al tanto con los avances. Gracias de nuevo por los aportes, a el hombre ebrio de la fotografía, a nige, a todos en general. Próximamente quizás toquemos el mando final por el pequeño bote de aceite. Los mantendré informados. Allí dos videos de como aprendo a conducirla. Saludos.
Translation....... Hi guys and best wishes to all. Sorry I'm writing in Spanish but I'm sure Nige can translate into English so you can understand better. I've been MIA for a few months, busy with other stuff. Also thnigs have been a bit paralyzed as a result of the pandemic. We've made a lot of aesthetic improvements. I already had 7 new teeth with adapters, I just had to buy 1 more to make a complete set. We did some testing in May but the engine still had a tendency to overheat. I removed the radiator for cleaning and now it's much better. This week I put it to work and have already run it for 4 hours, it runs pretty good. I wanted to say Hi and post information regarding progress. Thanks again for all the help, to the drunk guy in the photos, to Nige, and everyone else in general. Soon I hope to address the final drive that has a small oil leak. I'll keep you posted. Above are a couple of videos showing how I've learned to operate the machine. Best wishes.