I have a 2005 CAT257B. The lift arm cylinders will leak down fast while running the machine. You have to hold back on the joystick to keep it up. If you turn the machine off it does not leak down. I have repacked the cylinders and it still does it. Also, when the machine warms up it does not want to turn. When you first crank it it turns great. It tracks straight, does not pull to one side. Just put a new radiator/hydraulic cooler on it. & new hydraulic filter. I have owned the machine for 6 years. It has had these issues since I bought it. S/N - CAT0257BVSLK03751
It's pilot operated, so when there is no pilot pressure (engine off in other words) nothing will move. The problem is quite likely to be tired springs, worn seals, etc, in here ............
Thank you for your reply. Just ordered a spring seal kit. What are your thoughts on the machine not wanting to turn once the machine heats up?
My first suggestion would be a complete test of the hydrostatic drive system and see what numbers it throws up compared to the specification. Out of interest what oil are you using in the hyudraulic system.?
I run cat hydraulic fluid. I put a pressure test gauge on all the ports. I think it calls for 3200 PSI. The lowest pressure I saw was 3000psi
All I can suggest is do all the tests mentioned in the attachment above in the order that they are specified and then post all the results. The document is a total of 21 pages and covers far more than what you have apparently tested so far.
I replaced the springs (# 11) under the joystick. That fixed my lift arm cylinder drop. I have been dealing with that issue for 6 years! Thank you. I am going to try and test the hydraulic system sometime this weekend hopefully.
You're going to need a fair amount in the way of pressure gauges and tooling. MHO - Don't skimp on the tests, especially when it comes to tooling. Do each one using the test equipment specified in the order that they are listed in the document. Don't try to "make do" with pressure gauges that are not the specified range for the test in question. Use the correct range of gauge for each test or you might end up missing something subtle that could be the key to all the problems.
My MB1 & MB2 ports are supposed to be at 5555psi. I am only getting 4200psi from both ports. I’m going to try to adjust the relief valves to get the right pressure. Someone put this pump on the machine right before I brought it.
It is a Cat pump (as opposed to a "will fit") I hope.?
Yes. The tag says CAT 236-5106, 06/05, 13680Z
236-5106 is only the Part Number for the Work Tool (implement hydraulics) pump, not the hydrostatic drive pump. The hystat pump should have a tag with either 229-8216 or 289-6340 on it.
I have been adjusting the MB1 & MB2 relief valves. I can not get more than 4500psi out of it.
Have you replaced the hydraulic filter recently.? If not then I suggest that you should do that, then cut open the old one and look for "sparklies" in the filter media. See this helpful VIDEO that will give you an idea how to do it. Yes, I know it's an engine filter but the principle is the same, especially the part about squeezing the filter media in a vice. Post photos of what you find.
I just put a brand new one on today before I started doing all the checks. I saved the old filter so I could cut it open. I will post pics when I cut it open.
That'll work.
I ordered a filter cutting tool. It will be here Monday. I worked the machine today. It feels like it has less power now. Could I have tightened the spring tension on the relief valve to much? Is there another relief valve that I need to look at. Like a main one for the pump?
I'm having similar issues with my machine. Did you find a fix for yours?
I finally got around to do all the checks. I found that my charge pressure was about 100psi to low. I took the relief valve out. I know this was not the correct thing to do but I did not have any of the washers to put in to adjust the pressure. I decided to stretch the spring a little bit just to see what would happen. I stretched it and put it back together, luckily when I checked it the change pressure was within the tolerance of what it should be. Then I checked the crossover relief valves and it brought the pressure up from 4500psi to 5200psi. Still lower than what it should be but it was an improvement. I tested the machine out this weekend. I did notice a slight improvement but still pretty weak turning when it warms up. I also added some hydraulic fluid booster to see if that would help. (See picture of what hydraulic booster I used) I did finally cut my used hydraulic filter open and I did not find any metal in the filter.
Good write-up. Sounds like in your case that a replacement spring in that relief valve is called for as a long-term fix. It might get the pressures even better aligned to specification.
Nige, could you possibly get a part number for that spring and the adjustment washers? I can not seem to find it anywhere. S/N - CAT0257BVSLK03751
Sorry I got the wrong valve. Assuming that this is the one you are referring to there are no serviceable internal parts. The complete valve #10 is P/N 204-1459. The 3mm thick external shims #7 are available under P/N 204-1456. The O-Ring #16 is P/N 6V-8352.
I think I have found the issue. My speed sensing pressure. It is supposed to be set at 375psi ( I think, I don’t have the paper work in front of me) the lowest my gage will go is 125psi and it would not even register on the gage. I finally found how to adjust it (I could tell someone had messed with it before, there were Channel lock marks on the cover that covers up the adjustment screw). I had to adjust it quite a bit (maybe 4 turns) before i could get the pressure to start increasing. I set it to the correct spec’s. I then had to check all the crossover relief valves because I adjusted them the other day. They pegged out my 6000psi gage. They are supposed to be set at 5555psi. I set them to the correct spec’s. When I test drove it, it is a completely different machine now. It seems to have SO much more power. The machine will turn on a dime now. I want to say thank you to Mr. Nige. I don’t think I would have figured it out without you. I was on the verge of selling the machine.
I guess that now you understand the importance of doing the tests in the order in which they are listed in the T&A procedure and not moving on until you have every one of the preceding values in the test sequence within specification. Extremely glad that you got it fixed.
I have another question. Machine hydraulic’s are running great now. Now I find that the hydraulic’s are over powering the engine at times killing the engine. If I have a full bucket and turn to fast the engine will choke down and die. Or if I am driving into a pile of dirt it to get a bucket full it will choke the engine down and kill the engine. Is this normal for this machine? Just not enough HP? Or is there something else that could be wrong? RPM’s are set to the correct specs. Just changed the fuel filter when I was doing all the hydraulic checks 2 weeks ago.
Which one.? #1 (the small inline filter) or #6.? Try taking a look inside #6 and check that it's actually full of fuel when you have the low power issue.
I replaced #6. #1 was not on the machine when I bought it and the screen in the mechanical pump would clog up so I added one in that spot. However I took it out the other day because I could never get it to fill up very much. The machine would run but I wasn’t sure if it was causing any issues with it not being full. So as of 2 weeks ago it is not on there. I also took the screen out of the mechanical pump and made sure it was clean.
I would strongly recommend going back to installing an inline filter. HOWEVER you do need one rated for diesel, most of the inline filters sold at auto parts stores will only work for gasoline. Either go with the OEM Part Number 1G-7206 or a NAPA3972 which should work in your application. Next step, remove the complete fuel filter/water separator assembly, and separate the filter from the head. Remove all the fitting, plugs, etc, and either rod through all the fuel passages in the head or blow through them with compressed air. Reassemble and test. Also next time you have a low fuel level in the tank try draining the water & sediment from it. The drain plug is close to the LH rear corner of the machine. If it's been a while you might be surprised at what comes out. Procedure is in the O&M Manual. While you're in the area try clreaning out the fuel tank cap to make sure the breather is clear.
Thank you. I will work on this tomorrow.
The best time to drain the tank of water & sediment is after the machine has been sitting overnight.
I am having another issue out of my machine. Ever since I bought it (about 5 years ago) I have been dealing with an over heating issue. The hydraulic fan use to turn really slow at ideal. Since I fixed the hydraulic issue it turns a lot faster now but still overheating. It’s really hard to get an accurate rpm on the fan. I have made sure the relief valve on the hydraulic fan is not set to low. I have added and electric fan to the top of the radiator/hydraulic cooler. I have put on a brand new radiator. New thermostat. I even tried to gut the thermostat and just put the washer back in. I have taken the water pump off and inspected it. Everything looked good on it. I ran my water hose and flushed out the engine block to make sure it flowed good. I filled up a bucket of water and put one side of the coolant hose in the bucket and ran the machine to make sure the water pump was pumping properly. Everything checked out good. I have added a temperature gauge so I can see what temp it is actually running instead of just relying on the alarm. It will get up to 230 - 240 degrees pretty fast. I’ll let it sit for 10 or 15 minutes to cool off then work it for 10 or 15 minutes until it over heats again. Do you have any suggestions on the next direction I should go? S/N - CAT0257BVSLK03751