ZD 21 Problem

[Camper Hal]

We have a ZD 21 with 700hrs on it. The entire hydrostat system was rebuild by
a Kubota dealer at 624hrs. Now the hydrostat system uses a quart of Kubota hydrostat oil every 4 hours of mowing. The dealer can find any leaks and has know idea where the fluid is going.
Does anyone have any ideas?

Thanks,
Camper Hal

 

[100 td]

Personally I would be taking it back to the dealer and escalate the problem with them. No second guessing, they need to assess it and find the problem and fix it. YMMV

 

[rentthis]

If it isn't leaking, could you have a bad seal at the pump allowing it into the engine to burn? If it's leaking a quart every 4 hours, the leak should be as obvious as a silver dollar in a billy goats butt.

 

[fatjay]

There's really no path to disappear into the engine. You'd need both the hyraulic pump seal to fail and the crank seal to fail, but then the it would end up in the engine oil, not in the pistons. If it is really disappearing, it's leaking on the ground somewhere.

I'd start by cleaning the bottom of the hydraulic pump, hydraulic motors, and axels with a degreaser and making that thing shine, then start the mower on the driveway over a piece of cardboard, and let it sit/idle for about 30 minutes, shut it off, and pull out the cardboard and look at the bottom of the hydraulic pump and see if there's any wet.

 

[kuboman]

It has to be a leak as the only connection between the engine and tranny is a drive shaft so it can be being burnt in the engine.