There are four system check relief valves (Item 1) [Figure 30-51-15] in the back of the hydrostatic pump.
Remove the relief valve cap (Item 1) [Figure 30-51-15].
Assembly: Tighten cap to 111 – 125 ft.-lb. (150 – 170 N•m) torque.
Check the valve cap O-ring (Item 1) and back-up ring (Item 2) [Figure 30-51-16], replace as needed.
Remove relief valve assembly (Item 3) [Figure 30-51-16] from the valve cap.
Check the conical spring (Item 4) [Figure 30-51-16] to ensure it is not broken or flattened.
Check the valve seat surface (Item 1) [Figure 30-51-17] for scratches and replace as needed.
Inspect the spring (Item 2) [Figure 30-51-17] for breakage.
Inspect seats inside case housing.
Do not disassemble the relief valve assembly. If replacement is required, replace as an assembly.
Factory setting on the relief valve is 5075 PSI (350 bar).