53
CLEAN AND INSPECT
1. Discard all O-rings and back-up rings. Clean all
parts in solvent and blow dry. Inspect polished sur-
faces of spool and damper piston for damage that
may cause binding or leakage. Inspect spool bore in
valve housing for damage or scoring. Inspect check
valve seat in valve housing and check valve poppet.
If the spools, bores or valves are damaged, the
entire brake valve must be replaced. Check the free
length of main piston spring. Replace if less than
3 7/16 in. (87.3 mm) long. Check the free length of
the check valve spring. Replace if less than 1 1/2 in.
(38.1 mm) long.
2. Inspect the 0.020 inch (0.5 mm) orifice in the end of
the spool to be certain it is open.
ASSEMBLY
1. Install new O-rings and back-up rings on the spool
and damper pistons as shown. It is important that
each back-up ring is on the correct side of its O-ring.
Take care not to cut the O-rings during assembly.
Let the spool and piston set for ten (10) minutes
before installing them into the brake valve housing.
This will allow the O-rings to return to their original
size after being stretched.
2. Install new O-rings on the plug and spool retain-
ers.
O-RING
BACK-UP RING
3. Lubricate the spool and damper piston O-rings with
hydraulic oil. Carefully install the damper piston into
the spool. Carefully install the spool into the valve
housing. Always install the spool into the valve body
from the plug end, so the O-ring enters the bore first.
Install the spring seat, spool spring, damper piston
extension and spring retainer.
4. Install the check valve poppet, spring and check
valve retainer.
5. Install the motor drain check ball, spring and fitting.
6. The brake valve is now completely assembled and
ready to be installed on the winch motor.
