New Holland T4.75 power star hydraulic problem

[Ncjim919]

The loader jerks really Bad when the oil is hot . I have replaced the pump, loader control valve, relief valve, change filter and oil ,replaced all suction hoses on suction side of pump ,changed the quick couplings and switched the hoses on the lift and replaced the cylinder packing . Installed a flow meter on the lift hose, I have 5.5 gallon a minute at idle and it will drop to around 3.5 when it jerks and go back to 5,5 till it jerks again and pressure stays around 500 when lifting . Pump puts about 11 gallon at 1500 rpm’s . When the oil is cold it does not jerk the warmer it gets the worst the jerking. I have talked to the dealers around here they were no help. Any recommendations you have will be very helpful.

 

[used red MN]

Hello Jim, welcome to YT! Well as you can see not much response here. I would recommend you post this on New AgTalk Machinery Talk
The majority of poster there are active farmers. This tractor may be in the “smallish” range for most modern farms but there is a chance someone there knows something about your problem. Good luck!

 

[rustred]

what pump do these tractors use? and is there a charge pump on the pump? there should be an adjustment for that.

 

[Ncjim919]

It is a gear type pump does not have a charge pump .The pump is mounted on the side of the motor the discharge line goes to the loader mid mount valve and a separate lines feeds the remotes and 3 point hitch .