9
2. Remove the tappet head and manual override assembly
from the wheel cylinder body, Figure 15. Separate the
tappet head from the manual override wheel.
3. Using a blunt screwdriver, pry the dust boots from the
housing and discard.
4. Carefully blow out both piston assemblies from the
cylinder housing using low pressure shop air. Remove
the small spring and locator assembly.
5. Unscrew the adjuster shaft assembly from the piston.
Note: Do not dismantle the adjuster shaft assembly.
6. Using a small screwdriver, with the end rounded and
polished, pry the seal from the piston, taking care not
to score the seal groove or piston surface.
EXPANDER DISASSEMBLY
Before proceeding, clean the exterior of the expander unit
and make sure the work area, tools, and hands are clean.
Place a clean sheet of paper on the work bench surface.
1. Place the expander unit in a bench vise with padded
jaws.
2. Compress the wedge return spring and remove the pin,
Figure 16. Slowly release the spring pressure and remove
spring along with the ferrule.
3. Use snap ring pliers to compress and remove the circlip
(snap ring), Figure 17.
4. Remove the dust boots from both ends of the expander
housing and discard. Note: The dust boots should not
be reused and must be replaced.
5. Remove the abutment tappet, input tappet/ piston and
stop pin from the housing.
6. Remove the wedge assembly, wedge seal, retaining ring
assembly and washer.
7. Push the roller tappet/piston from the housing in the
direction of the input tappet/piston, Figure 17. Note: Do
not slide the roller tappet/piston past the wedge turret.
8. Remove the bleed screw.
9. Using a small screwdriver, with the end rounded and
polished, pry the seals and o-ring from the input and
roller tappet/piston taking care not to score the seal
grooves or piston surface.
CLEANING AND INSPECTION
Discard all of the old parts that are to be replaced with
parts furnished in the repairs kits.
Clean all of the metal parts with unused DOT 4 brake fluid
or suitable solvent. Do not use gasoline or hot water solution
on metal parts.
FIGURE 18 - EXPANDER LUBRICATION POINTS
Clean all rubber parts that are to be reused with clean DOT
4 heavy duty brake fluid. Place on clean sheet of paper to
dry.
Inspect all of the parts that are to be reused as outlined
below. Replace those parts that are damaged or excessively
worn.
1. Wedge assembly. Check the wedge shaft and wedge
surfaces for scoring. Check the rollers for scoring, pits,
cracks, and flat spots. Check the roller cage for fatigue
cracks.
2. Abutment Tappet. Check the abutment tappet for any
nicks, burrs or corrosion. Check the brake shoe web
slot for any burrs or damage. Smooth with a fine emery
cloth or clean.
3. Tappets/ Pistons. Check the outer surfaces for scoring,
pits, or nicks. Check the seal ring and o-ring grooves for
any nicks, burrs, or corrosion. Check the brake shoe
web slot of the expander input tappet/piston. Check the
inside of the piston for damaged threads. Smooth with a
fine emery cloth or clean as required.
DOT 4 FLUID
DOT 4 FLUID
DOT 4 FLUID
GREASE
GREASE
GREASE
