computerfan
Guest
It sounds like you have replaced everything except the foot and inch valve. The foot and inch valve is mounted under the cab and is connected to the inching pedal which is in the cab. The forward and reverse high pressure relief valves are pilot operated relief valves. This means that the relief pressure is set by another valve, in this case, the foot and inch valve. Inside the foot and inch is a needle and seat and a spring. When your foot is off of the inching pedal, the spring holds the needle on the seat until the relief pressure setting is reached. When the inching pedal is pushed in, the needle is pushed away from the seat, all pressure is released and the combine stops. The relief pressure is set by adding or removing shims under the spring. The needle and seat can go bad, the spring can break, and a new spring will weaken after a period of time and will need to have more shims installed under the spring to bring the pressure back to where it should be. I like to see at least 6500 psi. All pressure checks should be made with the hydraulic oil at operating temperature. One more area for your mechanic to check. Hope this helps.