Mini-Ex Some controls/tracks/blade not working

sikmusicfreak8 · Mar 27, 2021

So I bought a Gehl 602 (Mustang 6002) excavator at auction with known hydraulic problems. I was under the impression that all hydraulics weren't working, and assumed I needed to replace the pump. That was not the case.

So upon firing the machine, I can:
-Boom up
-Curl bucket in/out
-House rotates left/right

I cannot:
-Track machine forward/backward
-Blade up/down
-Boom down
-Extend/crowd the stick

Not sure if AUX circuit it functioning, dont have anything to test that yet.

I am kinda hoping I have an issue with some solenoid, or something with the pilot valve/circuit. Doesn't sounds like a pump to me, as I do have some controls working.

Am I barking up the right tree? I appreciate any insight, just looking for a direction to follow.

Thanks!

bindian · Mar 28, 2021

Get a hydraulic system diagram and see what the common points are in the controls that are not working. Make sure this common point is not connected to what is working. If you have two of them, swap them to see if the problem moves with the swap. That is what I would change first. It is not a pump UNLESS your have a two part pump or two pumps. Then it might be a pump or the back half of your two part pump.

To check a pump, swap lines between something working and not working to see if the problem stays or migrates. Or start going crazy installing pressure guages. But then you need the factory pressure specs.

When all else fails, call a factory mechanic and see if you can pick his brain. Get on Heavy Equipment Forum. More ex wrench turners there.
hugs, Brandi