Hi there, I have an old Kubota kh28 that that’s I’ve got new hydraulic pump for, can anyone advise on how to check the relief valves on this machine want to make sure there set properly with the new pumps on. I know how they work etc just not sure on the right procedure for the overload valves and the main reliefs, thanks for any advise
Your Kubota KH28 uses three gear pumps rated at ~2,700 PSI . Typical working pressure is 2,400–2,900 PSI . Always confirm exact specs in the service manual before adjusting. 1. Warm the system Run the machine 10–20 min until oil is hot. Cold oil gives false high readings—set reliefs HOT. 2. Set the main relief first Install a 0–400 bar / 0–5,000 PSI gauge at the main test port Back the adjuster out slightly At rated RPM, stall a main function (boom up) Increase pressure in 1/8–1/4 turns until spec (~2,600–2,900 PSI) Hold adjuster and lock jam nut 3. Set circuit reliefs One function at a time (boom, arm, bucket, swing, etc.) Stall that function fully Set equal to or slightly below main relief Never exceed system rating Lock jam nuts 4. Verify in real work Operate normally and check for: Smooth relief action No excessive noise Balanced function power 5. Record final pressures Log main and circuit settings for future troubleshooting.