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Kubota KX91 Hydraulic Pump Leak Question

Willof72

New Member
Joined
Mar 27, 2026
Messages
3
Location
Pennsylvania
Being new to the "heavy" equipment field, I really needed an excavator for my construction side gig. Shovels and posthole diggers suck. After months of trying to find one, I finally acquired a Kubota KX91-3S…with 1,771 hours on it. I REALLY wish I had known someone that knew what to look for, as I’m finding out just how expensive they can be. No complaints but ouch. Within the first 100 hours of using it, I’ve replaced all filters & fluids, top/bottom rollers, tracks, bushings and 2 hydraulic lines. Now, I’ve been noticing something leaking onto the right rear track. Hydraulic fluid. The hydraulic pump attaches to what looks like a “bell housing”, which of course is attached to the engine. On the “bell housing”, rearward facing and about in the middle of it, is a ¾” hole and I believe this is the source for hydraulic fluid leaking. I noticed there was an old Pig pad under it, so it most likely had been leaking for some time prior.

If my assumption is correct…The front o-ring on the hydraulic pump is failing.

  • Can I install new o-rings in the pump easily? Or just pony up for a new pump?
  • Are these hydraulic pumps easy to remove/reinstall (room-wise)? There isn’t much room there and i don't know if I need to remove rear counterweights (any don’t really want to do this).
Thanks you all in advance for any info help. Will
 
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