Where to focus? (hydraulic motor seal question)

[Richard]

Hydraulic mower. I've rebuilt the motors that power the blades several years ago. Discovered I've got some dampness UNDER the deck....so something is leaking. Not a blow out leak but leaking none the less. (first start this spring, mower was VERY low on oil and I was baffled as to where it went.....now I know!

Anyway, Talking to dealer about finding and obtaining the parts to again, rebuild two motors. I've no issues taking them apart and putting back together BUT have no experience in diagnosing....

The second page is where I'm diving in. Unless a part is blown up (showing it's obviously an issue) if oil is seeping out the BOTTOM of the mower, what parts might I want to closely focus on here?

My logic would be the seal like #5. That said, for all I know 6, 7, 8, 9 might provide a seal too. Or, maybe 12....

Still waiting for the dealer to get back to me about availability and cost. Wish they'd hurry.... in the meantime, the grass is growing!

 

[oldnslo]

Item #1 appears to be the shaft so it is also a suspect as a point of leakage. Since this motor does not appear to have a case drain there must also be some form of high pressure seals to prevent high pressure oil getting to item #1 unless that is not a conventional lip type shaft seal.

 

[Richard]

case drain is on first motor, this is probably second motor that receives from first. no drain on this one

 

[oldnslo]

If this is second motor and there is no load down stream then item #1 would be my first guess at what is leaking. As to why it is leaking I would check to confirm no restriction in return line from this motor to tank. If you dismantle the motor would also inspect gear housing, side load seals, etc. for wear or damage since excessive leakage to the shaft seal area can cause shaft seal to fail.

 

[Richard]

I've got a thread about relief valves. The leaks are probably my fault. I had tinkered a bit with the reliefs then, tried to put back.... back to adjusting them.... so they're a mess. I need to get some gauges so I can deal with numbers & facts. At one point, I'm pretty sure they were too snug. PRIOR to that adjustment, the 'drivers side' set of blades shredded all that came to it....whereas the 'passenger' blades could be overcome with the grass (that the first set were shredding). NOW, after my brilliant moves, I've got some dampness under the drivers blades that wasn't there before I tinkered. So I think I overtightned the relief and created this mess out of my own expertise!!

 

[Richard]

As to why it is leaking I would check to confirm no restriction in return line from this motor to tank.

Forgot to insert the quote in above post.