Caterpiller 242b hydraulic problems

[1985GT]

Hello,



We have a 2005 242b skid loader, the machine blew a seal between the two pumps. We have replaced the seals and refilled they fluid. Now we are having problems with the lift arms raising. They will only raise when the machine is reved up. The machine will not lift the arms at any engine speed with the bucket attached nor will it roll the bucket back.

Most of the hydraulic fluid was leaked out of the system when the seal blew. We checked all of the other hoses and did not find any other leaks. We also replaced the filters at this time and cut them open. We found no traces of metal.


When the seal blew the machine was shut down pretty quickly and we picked the machine up to move it in to the shop to work on it. Is there a bleeding procedure for the hydraulic system? Any other thoughts?
..

 

[02Dmax]

does it travel ok? I assume you're talking about the o-ring between the pump mounted closest to the front of the machine and the main hydrostat?

 

[1985GT]

Yes it travels fine, and it will curl the bucket when it is not attached with out reving the machine up.

Yes we replaced the O-ring seal and the lip seals on the shaft. Two of the four allen head bolts broke on the mounting flange. The two bolts that actually mount the work tool pump to the main pump were fine.

One of the things I did not check was the fan to see if it was spinning fine from what I understand the pump also runs the cooling fan.

 

[02Dmax]

Did the splines on the shaft and socket look ok? I've seen them round the splines off if they run loose for awhile.

 

[1985GT]

Yes splines were in good shape.

 

[02Dmax]

Well, my best guess is that the pump is shot. Usually they don't blow out that lip seal unless something is wrong internally. All the indicators point to this being the problem.

 

[1985GT]

The lip seals didn't go bad the o-ring between the mounting flange and the work tool pump. I believe the only reason the seal went bad is because the two bolts broke for some unknown reason. I'm hoping the pump isn't shot, the machine was shut down quickly when the leak was discovered, and before it shut down everything was working fine.

Thanks for the help.

 

[02Dmax]

Only other thing I can think of is to make sure its getting plenty of fluid to the pump. If I remember right there's just a flexible rubber hose that comes off the bottom of the hyd tank that feeds that pump and is just hose clamped on. Make sure the clamps are tight so it can't suck air and that hose isn't kinked or have any blockage in it. I assume you took the mounting plate off the pump to get the broke bolts out?

 

[1985GT]

Yeah the mounting plate was removed to remove the bolts. Will have them double check the hose clamps. Also will take a look at the fluid to see if it is sucking in air, had not noticed it before.

 

[Digdeep]

Any thoughts of taking it to your local CAT dealer just to get it fixed once and for all? I'm guessing that this isn't a machine you use regularly.