Have a bobcat 943 that everything operates as it should for about 10 minutes or until the hydro oil is warm. Then the left side drive gets weak, if I'm pushing into a dirt pile it will stop moving completely on that side. Reverse still works although it makes the drive motor squeal under load. Anyone have any idea what to look for?
Sounds like a bad drive motor. You could monitor charge pressure and see if it changes when the problem occurs. Then remove and cap off the drive hoses at the pump, and run the same test with the oil at operating temp. If the charge pressure stays steady, the problem is in the motor. If it's still falling off, the problem is in the pump
Well drive motor tested good. So I went ahead and blocked off all the hydraulic lines to that side. When I do forward motion on the stick the engine loads/bogs is very minimal. But it is much much more noticeable when reverse is applied. I made a short video on YouTube , sorry for the bad quality.
there were a couple variations with the control system, this is just a theory, but i wonder if the servo is leaking internally, not letting the pump get to full stroke...
I wondered about that too. The right side actuator arm is very easy to rotate compared to left side. It's almost like there is not much fluid in right side of pump.