MHarryE
Elite Member
- Joined
- Feb 15, 2009
- Messages
- 2,946
- Location
- Northeastern Minnesota
- Tractor
- Kubota M7-171, M5-111, SVL75-2, RTV900XT & GR2120; CaseIH 1680 combine
Here are 2 items from my hydraulic pump/motor failure analysis manual. As shown here and in my experience, a sticking piston will usually break the retainer plate and yours appears sound. Still it explains how to identify a sticking piston by scuffing, abrasion marks on the piston.
I can't find my collection of failed piston - my wife has a different opinion of art than me so she stored them away where I can't quickly find them. I know I've posted pictures on this site before for trouble shooting help.
Under the conditions you describe, there should not be a viscosity problem. Still I do not understand why Kubota does not have a hydraulic temperature warning on their tractors. Its not that they won't overheat - I've measured temperatures beyond hydraulic component supplier limits on both my M135GX and L5740 - Here in cool Northern Minnesota. M was due to a faulty valve that kept the system at continuous relief pressure. L was operator abuse - I worked it too hard in dirty conditions that partially plugged the oil cooler. Engine temp alert they have but equally expensive hydraulic system no monitor. I keep an I-R thermometer on each of my tractors.