There is pressure loss in the cylinder due to a worn piston ring or a scored housing bore.

1. Disassemble the steering gear.
2. Inspect the ring and the housing bore.
3. Replace the affected components.

The valve springs and the valve body to the worm seal leaks.

1. Disassemble the steering gear.
2. Replace the seals.

The valve body leaks or the fitting spool is loose.

Replace the valve.