Tractor Repair: Case 1370, suction screen, brake valve

Question
I have a very eldery neighbor who is having trouble with hydraulics on his Case 1370.He claims the power steering fails,or becomes partially disfunctinal at times.(often)He has changed the hydraulic filters,but the problem remains.I owned two 2470's when I farmed.As I recall,the 70 series have a relief valve that is accessable without splitting the tractor,and also has a primary screen ahead of the filter,but like all of us,the "memory bank" is starting to malfunction.I would appreciate any info you can provide pertaining to this problem.
The owner of the tractor didn't mention problems with the remotes,or transmission.
Thank You,
Mark Alloy

Answer
Hello,

  The hydraulic system on a 1370 is very different from a 2470.  The steering relief valve is located in the top of the power brake valve.  The steering pressure can be checked at the pump or at the steering cylinders on the front axle.  The hydraulic pump is a dual pump, with one section being just for the steering and brakes.  If the pressure is good at the pump but weak at the cylinders, then the relief valve is bad.  If the pressure is weak at the pump, but the rest of the hydraulics are OK, then you can assume that the steering supply section of the hydraulic pump is worn.  The pressure at the steering cylinders should be 2200 to 2400 psi. with the oil at 120 degrees F.  There is an internal suction screen inside the rear frame, but the tractor would have to be split between the transmission and rear frame housings to get to it.  If the other hydraulics all work OK, then you can assume that the screen is OK.  The power steering hand pump (the control unit that is operated by the steering wheel) should have no more than 1 rpm of slippage at the steering wheel.  To check, start the engine and turn the steering wheel all the way to the left or right and continue to try to turn it after the wheels hit the steering stops.  If there is more than 1 rpm of slippage with 72 inch lbs. of force on the steering wheel, cap off the hydraulic lines at the steering cylinders and try again.  If the slippage improves, the steering cylinders have internal leakage.  If it does not improve, the hand pump is bad.