12
Section 2
Hydraulic Brakes
NOTE: Some FSH brakes, which do not have an
optional parking brake, have an upper coil shoe
return spring in place of the “U” spring.
6. Release and remove the shoe return spring.
7. Push down on the shoe retainers so that the
retainer nails can be reached with pliers.
Hold the retainers so that they do not twist
while you rotate the nails 1/4 turn. Remove
the retainers, springs and retainer nails.
8. Remove the brake shoes.
9. On brakes with the mechanical parking brake,
remove the cotter key, spacer, spring clip and
lever assembly.
10. If complete disassembly is necessary,
disconnect the hydraulic line and remove the
wheel cylinder attaching capscrews and
wheel cylinder.
11. Clean and inspect all parts. Refer to Section 4.
Assemble FSH Brake
CAUTION
Do not permit grease to contact the brake drum
or linings. Grease on the linings can cause poor
brake performance. Contaminated linings MUST
be replaced.
1. Before assembly, apply a thin layer of
Meritor specification 0-616 brake lubricant
such as Texaco Thermatex EP-2 grease or
equivalent (listed on page 31) to the
following parts:
a. Push rod ends of shoes and cylinder.
b. Surfaces of the adjusting cams and the
matching surfaces of the brake shoes.
c. Surfaces of the shoe support pads on the
backing plate assembly and the ends of the
shoe webs that slide against the anchor
bracket.
2. Install the wheel cylinder to the backing plate.
Tighten the wheel cylinder attaching screw and
capscrew to 25-35 lb. ft. (34-47 N•m).
3. Connect the hydraulic line.
4. If a mechanical parking brake is used, install the
lever assembly, spring clip, spacer and
cotter key.
5. Install the brake shoes in position so that the
push rod ends of the shoes are engaged with
the wheel cylinder or push rods.
6. Assemble the retainer nails, springs and
retainers. Lock the nails in position by pushing
down on the retainers while you twist the nails
1/4 turn with pliers.
7. To assemble the shoe return spring, put one
hook in position in a brake shoe. Pull the spring
open to install the opposite hook in the
other shoe.
8. Assemble the retainer spring clip into the
brake shoes.
9. On brakes with automatic adjustment, you must
tap the shoes with a soft mallet until the brake
assembly will fit into the brake drum.
10. Bleed the hydraulic system after all the brakes
are assembled. (See page 19)
Adjust FSH Brake
1. FSH brakes with automatic adjustment will
adjust to the correct lining to brake drum
clearance when you pump down on the
brake pedal to set the adjuster. These brakes
have 9/16 inch or 3/4 inch adjustment
bolt heads.
NOTE: Each brake shoe must be adjusted
separately.
2. The manual adjustment FSH brakes have two
eccentric cams that can be adjusted with
either an 11/16 inch or a 15/16 inch open end
wrench on the two adjustment bolt heads.
a. Position the wrench handle horizontally,
away from the brake, then rotate the
handle down to move the lining closer to
the brake drum. Adjust the shoes until a
slight resistance can be felt when the brake
drum is rotated by hand. Figure 2.14.
b. Turn the adjustment bolt head in the
opposite direction until the brake drum can
just rotate freely.
c. Adjust the other shoe after you complete
the first shoe adjustment.
