Hi everybody! Complete rookie here so forgive me for my lack of knowledge. Bobcat 335 excavator. My left track has started getting weaker and weaker. It will tracks badly to the left, and can barely push with the blade now. However reverse seems to have equal power, and tracks fairly straight. Track tension is fine, and all rollers and idler spin freely. I also pulled the floor off to make sure the lever linkage was fully pressing in the plunger on the travel control valve(low pressure?). I took the case drain line off the travel motor, and ran it with enough resistance to the point it stalled out. I had zero case drain. Which leads me to believe the motor is ok, and to look up stream in the hydraulic system. The next thing the shop manual states is to test main relief pressure, but I feel other circuits would be acting weak as well.?. I ordered a kit to at least test pressure anyway. After that it states swivel joint leaking. Well if it is leaking it's internal, and going to case drain.(no external leakage) There is no procedure for troubleshooting that as far as I can see besides using a flow meter on case drain line possibly.. Maybe moving/swapping hoses around, but I'm not there yet. Last would be the counterbalance spool sticking which is only listed in the troubleshooting section. The travel motor disassembly/assembly never references either spool as a counterbalance. Just the two-speed spool and main spool. A friend who works on his all the time told me he thought it was the control valve(high pressure?) o-rings. I'm really curious to fully understand, and properly troubleshoot the hydraulic systems on my machine. Makes sense before tearing into anything more. Kudos to hydraulic mechanics, and engineers! The S.M. "Description" of the hydraulic control valve has two main relief valves.(see pic) A front(2650 PSI), and rear(2900 PSI). I'm not sure the correlation to the testing/adjustment of the main relief valve. The PSI's are different, and confusing to interpret. S.M. states target pressure for main relief to be between 3380-3530 PSI which doesn't match either front or rear referenced valves. Has anyone had a similar experience, or can point me in the right direction to troubleshoot this more? Thanks for your time, and any help/advice you may have.
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