13
RED - Park brake expander end on both LH and RH brakes.
GREEN - Wheel cylinder end on LH brakes.
YELLOW - Wheel cylinder end on RH brakes.
2. Remove the elastic bands from around the wheel cylinder
used to retain the pistons for assembly.
3. Push the abutment ends of the brake shoes into the
slots on the piston and tappets.
4. Attach the swan neck end, end opposite the loop in the
spring, of each return spring to the brake shoe web as
shown in Figure 25. Using the tool, Figure 13, hook the
other end of the return spring into the shoe web.
5. Install the brake drums.
6. Repeat with opposite wheel.
7. Ensure that the wedge stem is centralized.
8. Fit spring brake chambers to brakes per vehicle service
manual.
9. If new wheel cylinders or expander units were installed,
or the brake system drained, refer to the vehicle service
manual and bleed the brake system.
BRAKE SHOE ADJUSTMENT
1. Manually adjust both wheel cylinders through the
adjusting holes, Figure 10, until the shoe to drum
clearance is less than .76 mm (.030"). Check the shoe
to drum clearance by using a feeler gauge through the
lining inspection holes, Figure 26.
2. Apply the foot brake pedal to centralize the brake shoes
and release. Recheck the shoe to drum clearance; if
not 0.51 to 0.76 mm (0.020" to 0.030") manually adjust
the wheel cylinder until those dimensions are reached.
3. Replace all rubber grommets previously removed from
the backing plate (dirtshield).
Note: Due to manufacturing tolerances, it is unlikely that all
shoes on an axle will run at the same drum clearances.
No detrimental effects will result from this condition,
and no attempt should be made to standardize the
clearance.
4. Correct and full adjustment will only occur with the drum
rotating; i.e., with the vehicle moving. Pumping the brake
pedal with the vehicle stationary will not achieve proper
adjustment.
5. Refit road wheels.
IMPORTANT: Run engine and release park brake. Wind
the park brake chamber spring release bolts in place
until they bottom firmly in the unit. They should be
torqued to the vehicle manufacturer’s
recommendations.
6. Rotate each wheel to insure that the hydraulic system
has fully released parking brakes.
7. Apply parking brake and check that the wheels cannot
be rotated by hand.
8. Jack down vehicle. Run engine and release parking
brakes. Drive vehicle slowly and check service and
parking brakes, finally road test.
FINAL CHECK
IMPORTANT! PLEASE READ:
Before test driving any vehicle, first check the hydraulic
fluid level in the master cylinder.
1. Check the hydraulic fluid level of the brake master
cylinder. If the fluid level is more than 1/4 inch (6,35 mm)
from the top of the reservoirs, fill the reservoirs with DOT
4 heavy duty hydraulic brake fluid.
2. Depress the brake pedal several times to seat the brake
shoes against the drums. Recheck the fluid level of the
master cylinder reservoirs.
3. Check the brake pedal travel by pushing the brake pedal
as far down as possible. If the brake pedal free play
exceeds recommended dimensions, or brake warning
light is lit, refer to the vehicle service manual.
4. With the vehicle on a level surface in a parking or service
area, start the engine and apply the parking brake; test
for operation.
5. With the vehicle moving at slow speed, make a series of
light snubs and follow with a series of normal service
stops before making a panic stop. Make sure the service
brakes stop the vehicle in an even and straight line,
without any pulling to either side.
6. Accelerate the vehicle to a speed of 20 mph (32 km/h)
then apply the service brakes. A 30 ft. (92,4 m) stop with
the service brake from 20 mph (32 km/h) is recognized
as being satisfactory.
