Assembly Of Parking Brake Valve; Installation Of Parking Brake Valve; Inspection Of Parking Brake Valve; Cleaning Of Parking Brake Valve - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
B. Brake Assemblies (continued)
15. Assembly of Parking Brake Valve (refer to 32-40-00 Figure 407)
(a) Install O-rings on valve cam.
(b) Lubricate O-rings with hydraulic fluid (MIL-H-5606), insert cam into valve body and secure with
spring, bushing, washer, and self-locking nut.
(c) Install O-ring on valve, insert valve in the out porthole, install valve spring, and secure with
outlet fitting.
16. Installation of Parking Brake Valve
(a) Attach valve to bulkhead mounting bracket with screws.
(b) Connect fluid lines to valve.
(c) Connect control cable to valve lever. Ensure when valve lever fits in the closed detent, parking
brake handle is 0.062 to 0.125 inch of being fully in against the stop.
(d) Bleed brake system (refer to 32-40-00 Bleeding Procedure).
17. Inspection of Parking Brake Valve
(a) Inspect cam and seat valve body surfaces for excess wear and corrosion.
(b) Inspect cam assembly for burrs, scratches, excess wear, loose operating lever, etc.
(c) Check general condition of valves and spring.
18. Cleaning of Parking Brake Valve
(a) Clean valve parts with a suitable solvent.
(b) Dry them thoroughly.
19. Repair of Parking Brake Valve
Repair to valve is limited to smoothing burred or scratched surfaces and replacing O-rings.
20. Bleeding Procedure (referto32-40-00 Figure 601)
If brake system has been drained, has had parts replaced, or had had any line connection broken,
bleed it as follows:
(a) Place a suitable container at the reservoir to collect fluid overflow.
(b) Remove rubber bleeder fitting cap located on landing gear brake unit housing.
(c) Slide pressure hose from pressure pot over bleeder valve.
(d) Pressurize the pressure pot to 48 ± 2 psi. Open the bleeder valve.
NOTE: By watching fluid flowing into the reservoir, determine whether any air has entered the
system. If air bubbles are evident, continue filling the system until all air is out of the
system and a steady flow of fluid is obtained.
(e) Allow at least 2 gallons to flow.
(f) Simultaneously depress pilot's brake pedals approximately 1 inch in successive motions.
Return to neutral forcing any bubbles in the system downstream. Repeat with copilot's brake
pedals until no air is expelled at reservoir.
(g) Close bleed ports and depressurize system.
EFFECTIVITY:
040-999
Jan
10/9032-40-00