Brake Cylinder Service - BRADEN CH400B Installation Maintenance And Service Manual

DISASSEMBLY
The force of the brake springs can cause personal injury
or death if safety procedures are not followed. Review
safety requirements for using a hydraulic press before
disassembly of the brake cylinder.
1. Use a special compressor tool to compress the springs.
If a hydraulic press is available, only part A of the spring
compressor tool is required. Tighten the nut above part
A or if using a press apply hydraulic pressure to slightly
compress the springs and relieve the force on the re-
taining ring (53). Carefully remove the retaining ring
(53) with retaining ring pliers. Slowly unscrew the nut
above part A until spring force is no longer acting on
the spring stop (52); if using a hydraulic press, release
the force on the brake springs. Remove the compres-
sor tool.
2. Remove the spring stop (52), springs (55), and spring
spacer (62) from the brake cylinder.
3. Remove the brake piston (59). Remove and discard
both sets of O-rings and backup rings (27, 28, 30, and
31).
4. Remove the friction plates (25) and brake plates (26).
5. Remove the retaining ring (44) and bearing (58).
6. Remove relief valve (54) and clean in solvent. The re-
lief valve must be free of contamination and paint for
proper operation.
Clean and Inspect Parts
Thoroughly clean and inspect all parts, paying attention to
the sealing surfaces of the brake piston. Place each fric-
tion disk on a flat surface and check for distortion with a
straight edge. Friction material should appear even across
the entire surface and the groove pattern should be visible.
Replace friction disks if splines are worn to a point, disk
is distorted, friction material is worn unevenly or groove
pattern is no longer visible. Place each steel brake plate
on a flat surface and check for distortion with a straight
edge. Check surface for signs of material transfer or heat.
Replace steel disks if splines are worn to a point, disk is
distorted or heat discolored.
Check the brake release passage to be sure it is clean
and completely open. Inspect bearing for signs of dam-
age or excessive wear.
The minimum spring free length is 1.50 inches (38.1 mm).
If any spring free length is below the minimum, all of the
springs must be replaced.

BRAKE CYLINDER SERVICE

ASSEMBLY
1. Clean and inspect parts as described in the Disassem-
bly procedure.
2. Install bearing (58) in brake cylinder and install retain-
ing ring (44) in brake cylinder groove above bearing.
3. There are 7 friction discs (25) and 8 steel brake discs
(26) in the standard CH400B brake, but units with SPL
(special) in the model number may have a different
number. Coat the surface of the friction discs (25) with
hoist gear oil. Starting with a steel disc (26), alternately
install steel and friction discs in the brake cylinder until
all 8 steel discs and 7 friction discs are installed.
4. Install backup ring (27) and O-ring (28) in small diam-
eter brake cylinder groove. Install backup ring (31) and
O-ring (30) in large diameter brake cylinder groove.
The O-rings are always closest to the high pressure
side. Apply a light coat of grease to both O-rings and
backup rings and let them set a few minutes to take
shape in the groove before proceeding to the next step.
5. Lightly grease the O-ring sealing surfaces on the brake
piston (59). Ensure the O-rings and backup rings are
seated in the brake cylinder grooves and then gently
push the brake piston into the brake cylinder. If the
piston cannot be pushed in by hand, remove and check
the condition of the O-rings before proceeding.
6. Install the spring spacer (62) into the piston and install
the springs (55) in the spring spacer. There are 18
springs in the standard brake but units with SPL (spe-
cial), in the model number may have a different num-
ber.
7. Set the spring stop (52) on top of springs. The ma-
chined step in the spring stop should be toward the
motor side of the brake cylinder – the retaining ring will
The force of the brake springs can cause personal injury
or death if safety procedures are not followed. Review
safety requirements for using a hydraulic press before
disassembly of the brake cylinder.
seat against the machined step in the spring stop.
8. Use a hydraulic press or compression tool to compress
the springs and use retaining ring pliers to install the re-
taining ring (53) into the brake cylinder groove. Care-
fully release the force on the springs while ensuring the
retaining ring remains properly seated in the groove.
9. Apply a light coat of Teflon sealant to the threads of
relief valve (54) and install in brake cylinder.
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