Bad pump or wheel motor, how to tell?

Superduper · May 18, 2014

Hello. Finally got the engine running good on my project fixer deere zero turn. Now, found that only one wheel turns, so I can turn really good in a circle, but that's it. Presume that either the hydro pump or the wheel motor is bad.... leaning towards a bad pump. Anyone have any ideas how to confirm, or comment on the frequency of failure for pump vs motor?

One more bit of info in case it's relevant:
When I picked this up, the guys at the maintenance yard cranked open the hydro release so the mower could be pushed. Before trying to start this, I put the hydro's back into the "non-freewheel-mode" as per deere's instruction. However, it seems that the valve was only supposed to be opened 1/4 turn. When I closed the valve, it's clear that it was opened multiple turns. As such, the valve on the one side that's working opens & shuts very positively. The other one is hard to turn open/close and difficult to "feel" if its 100% closed although I have it cranked down as tight as I can (weakling) with a hand wrench. Wondering if opening that valve too many turns could've caused the issue.

oldnslo · May 19, 2014

Depending on the style of "towing" valve they can stick open causing the problem you are describing.

Superduper · May 19, 2014

We only put it in freewheel mode to load/unload from trailer. If it were stuck, is there a way to "unstick" it short of overhauling it? Looks like replacement pumps range from $500-$800.

Sent from my iPhone using TractorByNet

oldnslo · May 19, 2014

Some towing valves can be removed or replaced easily. On most lawn mowers that I have worked on they had buttons that where depressed in some manner to tow. If these towing valves were not used for an extended period of time they could get gummed up with crud and not spring back out once depressed. Not sure what your model has but on the older JD 317 - 318 deere these towing valves where removable and either replaceable or repairable.

Superduper · May 19, 2014

The pump has a hex shaped bolt (shown in pic, the bolt with hole through it) which is supposed to be turned 1/4 turn counter clockwise to release the hydro. Are you suggesting to back out and remove the bolt entirely and clean?

Coyote machine · May 19, 2014

I'd not tighten the bolt beyond snug so as to not cause any possible problems that could come from too much torque. I'd want to have a schematic of the way the bolt is connected to it's port before removing it completely. Did you use/see the mower function properly before purchase?
Try backing the bolt out, SLOWLY, until it's almost all the way out then try tapping the housing in the area of the bolt with a plastic head or dead-blow hammer. When screwing the bolt back in spray some penetrating oil on the threads and move it in/out without removing it completely. From what you describe it sounds like it may have some rust on the threads and when you think it's fully seated it might still be partially open. Reply with results.