TM 5-3895-359-14&P
Pitted cylinders which won't clean up with light honing
BRAKE MASTER CYLINDER
should be replaced. Piston to bore fit must not exceed
A brake master cylinder is used for each rear wheel brake
0.003." clearance after honing.
cylinder. The master cylinder linked to the brake pedal
Make sure compensating and secondary port and vent are
provides hydraulic pressure to actuate the wheel cylinders
open, not obstructed. Pre-lubricate all components with
to apply the brake assembly. The master cylinder casting
silicone brake fluid and reassemble.
combines the reservoir and master cylinder, cast
integrally. It is the compensating type, providing a port
Install valve seat washer. Install check valve assembly.
and vent to permit fluid expansion with temperature
Install spring and retainer. Install piston cup piston and
changes.
secondary cup, stop plate and snap ring. Install boot and
link. Install master cylinder.
a. To remove the master cylinder for either brake
system, it is necessary to remove the service access
WHEEL CYLINDER
cover on operator's platform, and by working through
cover opening and from underneath the machine, the
A single wheel cylinder is used at each rear wheel
master cylinders can be removed. Two bolts and nuts are
location, and is 1.5" in diameter. To remove the wheel
used to secure the master cylinders to mounting bracket.
cylinder, the wheel, hub and drum, and brake shoe lever
Disconnect the hydraulic lines and pedal linkage before
assemblies have to be removed. Then the hydraulic line
removing cylinder mounting bolts. The installation is
and two cap screws can be removed which will permit the
reverse of above. Bleed brake hydraulic system after
wheel cylinder to be removed outboard.
reassembly.
Like the master brake cylinder, the wheel cylinder can be
b. The master cylinder can be repaired by
repaired by replacement of internal parts and/or light
replacement of internal parts and/or honing of cylinder
honing to remove a series of pits or scratches, providing a
bore. Whenever the master cylinder is defective and a
clearance of more than 0.003" is not existent between
disassembly is made for correction, the internal parts must
cylinder and pistons.
be replaced.
Parts should be thoroughly cleaned in alcohol and
To disassemble the cylinder, remove the link and boot
inspected before reassembly. Cups should always be
from cylinder and remove snap ring (Items 1, 2, and 3,
replaced before reassembly. Install spring, cups, pistons
Figure 6). This will permit the removal of piston and all
and boots in this order. Parts should be pre-lubricated
internal parts.
with silicone brake fluid before assembly.
Inspect all parts and clean thoroughly in alcohol.
Install cylinder. Fill master cylinder. Install hub and
Figure 6. Exploded View of Master Cylinder
3-3
