1. Bleeder valve
7. Pressure plate subassembly
2. Rotating disc
8. Brake inlet port
3. Stationary disc
9. Self-adjusting mechanism
4. Housing backplate
10. Brake housing subassembly
5. Keyed torque tube
11. Brake assembling bolt
6. Torque tube spacer
Figure 12-53.—Trimetallic brake assembly.
the next locking position, as shown in view F. Secure
the threaded retainer with the wire retaining ring.
Replace the piston packings with new packings that
have been dipped in hydraulic fluid, and ensure that the
packings and adjusting pin stems are lubricated with
hydraulic fluid.
The piston assemblies are then installed in the
cylinder housing and forced to the complete brake-off
positions–bottomed in the housing cavities. The pistons
are supported against their linings to the brake-off
position. Use the press and the grip driver, as illustrated
in view G, to force the grips, one at a time, over the
adjusting pins until they are bottomed. The pistons must
remain in the complete brake-off position when the grips
are installed. Place the spacers over the adjusting pins
and install the bushings fingertight. Hold the bushings
in fingertight positions and install and tighten the
locknuts. Safety wire the locknuts, as shown in view H.
NOTE: On some brake assemblies, the ad-
justing pin bushing (adjusting pin nut) is
torqued to a specified value.
The brake assembly must be tested following
reassembly. Connect the brake assembly to a hydraulic
supply source. Bleed the brake assembly and apply 600
psi.
1. Housing backplate
2. Stationary discs
3. Rotating discs
4. Pressure plate subassembly
5. Pressure plate
6. Wear plate insulator
7. Wear plate
8. Bleeder valve
9. O-ring and backup ring
10. Piston
11. Piston insulator
12. Brake housing subassembly
13 Self-locking nut
14. Brake assembling bolt
15. Torque tube spacer
16. Keyed torque tube
17. Inlet bushing
18. Self-adjusting
mechanism
19. Self-adjusting pin
20. Return-spring guide
21. Return spring
22. Self-adjusting pin tube
23. Self-locking nut
24. Split collar grips
25. Retalning ring
26. Spring housing
27. Spring housing bushing
Figure 12-54.—Trimetallic brake assembly-cross section.
CAUTION
Before applying pressure, make sure that the
brake is assembled properly with all bolts
torqued and brake discs in position. Failure
to do so could result in injury to personnel.
Hold the test pressure for 2 minutes while you are
checking the brake assembly for leaks. Release and
apply the pressure 10 times to be sure that the brake
functions properly. The brake discs should be free when
hydraulic pressure is released. Allow the brake to stand
for 2 minutes with pressure released and check for static
fluid leakage.
12-60
