I posted a short question recently but didn't get a response so I will try a longer version of it. Cat 287B. S/N AZSA03121. Machine has about 2000 hours on it. The relief valves on the piston pump were leaking so my hired man changed the o-rings on two of them. There are four total. These are the 1 1-4" hex heads on the side of the piston pump. He cleaned up the machine and did some other minor maintenance at the same time. Shortly after the track motors nearly locked up. The tracks still turn but with a lot of resistance. The arms raise and lower normally. My guess is that we messed something up replacing the relief valves. I took all of them out and checked them. There are heavy spring mechanisms with a light spring underneath. I did notice that the upper front has a smaller inner spring than the others. I don't know the proper service procedure is on these so it would be great if someone could provide that. I can't seem to "release" the track motors. Is there a way to relieve the pressure? If there is any other insight anyone can provide I would appreciate it. Basic info on how the system works, etc. Also, could there be anything that happened coincidentally that is common with the track motors not wanting to turn? If I can't come up with anything I suppose CAT service is next but I thought I'd try here again.
Hi, I assume these are the valves that the o rings were replaced on. It is hard to help not knowing what your man has done. but if you could indicate exactly which valves he played with someone may be able to help. one thing to check is that no damage was done to the park brake solenoid valve or the wiring to it.as it is near to where he would be working The park brake is spring applied and needs power applied to the solenoid to be released. Damage to the valve or wiring will not log a code and the brakes will be applied. Mark
First thing you need to find out weather you having hydrostatic or park break issues.
Heavy springs is a port relief valves, light springs is shuttle valves, but Mark250 is right need to know exactly which valves were messed with, and it might be park breaks issue also.
If this machine have two speeds try to put in high speed and see if it will unlock your park breaks, might be just crossed over hoses.
The left forward crossover and the right forward crossover had o-rings changed. But after further investigation I'm almost certain it's something with the park brake solenoid. It is not getting any power. Also the machine behaves exactly the same with the wires disconnected from the solenoid. I found a trouble shooting procedure and got part way through it but had to quit for the night. Thanks to both of you for suggesting park brake issues. I will further investigate and let you know what I find.
Here's an Electrical Schematic just in case you have to troubleshoot the solenoid wiring.