Weak travel motor 335

[neller840]

I have a 335 excavator. The left track has started getting weaker, but only going forwards. Reverse it tracks ok(equal power), but forwards the left track is weak. I've tried easy things: checked track tension, control linkage, checked travel motor case drain.
A friend thought it was the travel motor's control valve o-rings. I am no hydraulic expert, and want to diagnose this properly, before I pull a valve manifold off. Any advice as to next things to check?

I was going to buy a pressure test kit, but I can't find great troubleshooting steps. I want to get a kit that will have everything needed to test this and other circuits. I know testing flow is really important as well. Any advice on tools to add to my arsenal for troubleshooting this?

Thanks for reading and any help you might offer!

 

[neller840]

Also was reading about making my own test kit from:

MEL1355 Pressure Test Kit for Bobcat 331 Excavators

Tazza, I've been doing a lot of reading and I came across a post, long ago, where you discussed checking hydraulic pressure etc. The manual says to use a MEL1355 Pressure Test Kit....well, the sticker shock has me thinking about making my own test kit. I came across a site that listed all the...

www.skidsteerforum.com

Trying to verify the test port on a 335 is a "Dixon 1PDF2....(1/4" NPT on backside)"

I would need 1/4" npt female to female hose and that would get me started? With a 5000psi gauge?

Also was wondering if I could test pressure out of the control valve for my left track, and then at the motor. Wouldn't a discrepancy show any swivel issues?

 

[neller840]

The test port is a Dixon 1PDF2.. It fits fine.

I talked with a service guy at bobcat. He said i should of had some light case drain. When I tested, there was barely had a drip.
He suggested swapping the lines, to see if the problem changed sides. So I swapped the lines from the right and left travel motors. The problem stays on that side. Two speed doesn't make difference on that motor either.

Are there any tests I can do on this motor? I have pressure gauges, but not sure how to go about testing it. Don't really want to pull it if i don't have to. Seems the only way to inspect the spools is to pull it. I was hoping to avoid buying a new motor if possible. Thanks for any advice