hydrostat problems

[cash]

I have this 825 bobcat that I have had for 20+ years I don't recall ever having this problem before, it is jerking on right side only. I have noticed it in a turn and a straight line. First thought it might be loose linkage shuttering but there is no slop in lever when it is not running. I must suspect worn plate in the pump, but what else is there to look for? Help is appreciated

 

[cash]

I HAVE MORE INFORMATION 1.) CHARGE PRESSURE at idle is 75psi no load book says 90 for this unit 2.) CHARGE PRESSURE full throttle levers full forward 100-psi, In reverse pressure will probably fall to 0 but I did not think that will help so I didn't let the pressure fall as far as it would. 3.) CHARGE PUMP INLET PRESSURE 10psi no load 4.) CHARGE PUMP INLET PRESSURE full throttle levers full forward 8-psi, In reverse pressure will probably fall to 0 Pulled the cover and run with drive unlocked the ports that usually have a steady stream of oil running out seamed normal until I put the right side in reverse and almost fully engaged lever then oil sprayed across the room. Looks grim to me but maybe a week charge check valve? The problem only shows up in reverse on the right side. ENJOY THE TURKEY

 

[Tazza]

Ok......
You mention oil spraying across the room, i assume this is your case drain hose? (the litle one going to the motor) If so, it could be as simple as bad motor seals or bad or stuck shuttle valve.
The charge pressure readings you are giving sound about right, Drive motor issues coule explain why it drops to zero while operating that side. All the charge oil is leaking out of the motor back to the reserve tank.
Just how hard is it to swap motors on this machine? some you remove the hoses and 4 bolts and simple swap sides. If the problem moves with the motor, you know its seals/shuttle valve or something to do with the motor and not the pump.
Sorry, never worked on one of these machines, so i'm only guessing here.

 

[coreya3212]

Ok......
You mention oil spraying across the room, i assume this is your case drain hose? (the litle one going to the motor) If so, it could be as simple as bad motor seals or bad or stuck shuttle valve.
The charge pressure readings you are giving sound about right, Drive motor issues coule explain why it drops to zero while operating that side. All the charge oil is leaking out of the motor back to the reserve tank.
Just how hard is it to swap motors on this machine? some you remove the hoses and 4 bolts and simple swap sides. If the problem moves with the motor, you know its seals/shuttle valve or something to do with the motor and not the pump.
Sorry, never worked on one of these machines, so i'm only guessing here.

Wish i could help. I have an 825 also and all I can think to say is poor you, Cash, 27 gallons of hyd oil......yuck.