4. Remove the brake linings from the pistons, the
brake housing, and the disc guide.
5. Clean the brake assembly components with
low-pressure compressed air. Wash all metal parts in
P-D-680 cleaning solvent. Dry with compressed air.
6. Check the release units for damage, nicks, and
gouges. If damaged, replace the complete release unit.
7. Check the brake housing for cracks and
cylinder walls for nicks or other visible damage.
Damage will necessitate turning in the complete brake
assembly to supply for disposition.
8. Install new linings in the housing cavities and
rivet on the disc guide lining. Friction fit will hold the
linings in the housing cavities. Do NOT use cement.
9. Install new linings in the piston cavities using
brake lining adhesive specified for such use (for
example, Pliogrip No. 3).
10. Install the brake disc into the brake housing.
11. Dip brake release unit packings from the
cure-date kit into the hydraulic fluid and install on the
brake release units.
12. Coat the piston of the release unit with a light
coating of hydraulic fluid and install in the housing.
Tighten the cylinder heads against the housing as
specified in the MIM or the 03 manual.
13. Reinstall the inlet plug, bushing, and bleeder
adapter into the housing. Use new packings that have
been dipped in hydraulic fluid.
14. Lockwire the cylinder heads, bleed the brake,
and test the brake for leakage and proper operation. Test
pressure for this brake assembly is 1,100 psi. Hold the
pressure for 2 minutes and check the assembly for leaks.
Release and reapply the pressure 10 times, and check
for proper brake operation and release of the discs.
Allow the brake to stand 2 minutes with pressure
relieved to check for static fluid leakage.
On dual disc brakes, as well as some single disc
brakes, the linings may be replaced without disturbing
the brake hydraulic system. See figure 12-51. In this
example, the shock strut is raised with a wheel jack until
the wheel is clear of the ground. The wheel is removed,
and the four internal wrenching bolts that attach the
brake housing to the backplate are removed. The two
setscrews located at each side of the brake housing are
unscrewed enough to allow removal of the seven axle
flange attaching bolts. Make certain the brake assembly
is supported before you remove the bolts, or damage to
the brake hose could result. Remove the brake linings
from the pistons, center carrier, backplate, and disc
guide. Riveted linings must be drilled. Snap-on or
friction-fit linings can be easily pried off with a common
screwdriver. Remove dirt and other foreign particles
from the brake assembly components by the use of
low-pressure compressed air. Wear safety eye
protection during this operation.
Clean the external surfaces of the brake parts with
a cloth dampened with P-D-680 cleaning solvent.
Replace any brake lining attaching buttons that are
damaged. The housing, backplate, center carrier, and all
bolts should be inspected for damage, cracks, or
leakage, as applicable. lf the brake has hydraulic leakage
or if the housing, backplate, or center carrier is damaged
or cracked, the complete brake assembly should be
replaced and turned in to supply for repair at the next
higher level of maintenance.
Inspect the disc for minimum thickness, maximum
width of the keyways, and warping. Check the disc for
warpage by using a straightedge across the face of the
disc. Instructions for straightening a warped disc can be
found in the applicable 03 manual. Replace a brake disc
that is worn excessively.
When a brake disc keyway is worn excessively or
elongated, inspect the brake disc drive keys within the
wheel assembly for damage and security. Replace the
drive keys or the wheel if the damage exceeds the
limitations specified in the applicable MIM.
The new linings are installed in the brake pistons,
the center carrier, and the backplate. The disc guide
lining is riveted to the disc guide. The pistons are pushed
back into the piston housing until a maximum of 1/8 inch
of lining is protruding beyond the housing. Assemble
the brake on the axle flange, and torque all attaching
bolts as well as the four internal wrenching bolts to the
specifications provided in the MIM. The fore and aft
axle attaching nuts on the brake housing must have their
flat surface toward the setscrew on the final torque. The
setscrews are tightened against the flat surfaces to safety
the nuts. Secure the four internal wrenching bolts with
lockwire. The wheel is installed and the shock strut
lowered. Perform an operational check to verify proper
operation. Specified steps throughout the lining and disc
replacement procedures and the final security of all
attachments require quality assurance verification as
indicated in the MIM.