20
5. Measure the brake spring free-length; minimum
free-length is 1 3/16 in. (30.2 mm). Inspect springs
for any sign of cracking or fatigue failure. If a spring
must be replaced for any reason, then ALL brake
springs must be replaced as a set.
ASSEMBLY
1. Begin brake cylinder assembly by placing the motor
support on the workbench with the motor mounting
surface down. Install a new o-ring and back-up ring
in the groove. Install the back-up ring close to the
motor mounting surface with the cupped side facing
the o-ring.
2. Insert first a steel separator disc into the motor sup-
port followed by a friction disc then alternate steel
and friction discs until seven friction and eight steel
discs have been installed. Finish with a steel disc on
top. It is a good practice to pre-lubricate the discs
with hydraulic oil or light motor oil prior to assembly.
Install the spacer ring on top of the last steel brake
disc.
3. Place the pressure plate on top of the brake spacer
ring. Hold the pressure plate down firmly by hand
and measure the clearance in three places, between
the motor support and pressure plate. The average
gap must measure between .153 in. (4 mm) maxi-
mum and .080 in. (2 mm) minimum. If the gap
exceeds the maximum limit, there may be too many
brake discs in the stack-up or the discs are distorted.
If the gap is less than the minimum, there are too few
discs in the stack-up or the discs are worn. If the
number of discs in the stack is correct and they are
not worn, then an extra steel separator disc may be
added to the stack to achieve the proper clearance
dimension. When the stack height is correct, remove
the pressure plate and continue assembly.
4. Lubricate the brake piston seal and motor support
sealing surface with gear oil or hydraulic oil. Install a
new piston seal onto the motor support with the seal
lip facing down.
5. Install the spring spacer and springs.
Failure to replace brake springs as a set may result
in uneven brake application pressure and repeated
brake spring failure from the older springs.
Brake spring failure could result in a catastrophic
winch failure from the metal fragments passing
through the gear train. A gear train failure may result
in loss of load control, property damage injury or
death.
