Brake selector valveexploded view

Aviation Structural Mechanic (H&S) 3&2 - How airplanes are built and how to maintain them
Page Navigation
471

1. Decal 6. 2. Nameplate 7. 3. Drive screw 8. 4. Retainer plate 9. 5. Machine screw 10. O-ring 11. Thread lock 16. Actuating shaft 21. Backup ring Shear plate assembly 12. Lock screw 17. O-ring 22. Seal spring Ball retainer 13. Stop plate 18. Backup ring 23. Body assembly Balls 14. Ball 19. Sure seal Bearing plate 15. Detent spring 20. O-ring Figure 12–45.—Brake selector valve—exploded view. This procedure completes the thermal crack test. In preparation for the shuttle valve opening operation test that follows, block residual pressure in the BRAKE port using a pressure gauge as the plug. With the RET port open and BRAKE port capped, apply hand-pumped hydraulic pressure gradually to the PMV port. There should be a simultaneous increase of BRAKE port pressure with PMV port pressure. At a pressure of 60 to 80 psi in the PMV port, pressure in the PMV port and BRAKE port should become equal. A gradual increase in PMV port pressure to 1,500 psi should result in a proportionate increase in the BRAKE port pressure. Any displacement at the RET port should not be considered leakage during this phase of the bench test. The shuttle valve closing operation test begins with 1,500 psi from the previous phase still applied to the PMV port. Reduce the pressure at the PMV port to 150 psi, and then rapidly to 0 psi. The closing operation is evidenced by the venting of hydraulic fluid from the RET port as PMV pressure decreases from 20 psi to 0 psi. The final phase of the bench test is the test for leakage. This phase is started with 27-psi hydraulic pressure trapped in the BRAKE port. There should be no evidence of pressure decrease when it is measured over a period of 3 minutes. Continue the test with the BRAKE port capped and the RET port of the valve in an upright position. Fill the RET port cavity and a leakage measuring device with hydraulic fluid. Apply hand-pumped hydraulic pressure of 30 to 37 psi to the PMV port. Leakage at the RET port must not exceed 0.5 cubic centimeter per minute. Immediately after application of pressure, measure the leakage for a 3-minute period. Disregard volume displacement because of shuttle valve transition if leakage is not in excess of 0.5 cubic centimeter per minute. Increase the pressure to 125 psi and maintain for a 3-minute period. There should be no evidence of leakage. Further increase the pressure to 1,500 psi and maintain for another 3-minute period. There should be no leakage. BRAKE SELECTOR VALVE Repair of the brake selector valve at the intermediate level of maintenance is limited to the replacement of cure-date items and parts listed under Spares and Replacement Parts Data in the "Intermediate Maintenance” section of the MIM. Figure 12-45 shows an exploded selector valve. Observe the arrangement view of the in which the 12-51

Privacy Statement
Press Release
Contact