TM 1-1520-238-23
Change 6
6-304.3
6.68.
MAIN TRANSMISSION ROTOR BRAKE ACTUATOR (GOODYEAR/ABSC)
DISASSEMBLY/ASSEMBLY (AVIM) – continued
c. Perform static leak/brake return pressure test.
(1) Increase test bench hydraulic pressure to 300 PSI maximum and open bleed valve. Bleed actuator until
fluid flow displays no air is present in bleeder outlet fluid. No flow is reason for rejection.
(2) Decrease test bench hydraulic pressure to 0 PSI. Close and torque bleed valve to 40 INCH-POUNDS. Use
torque wrench.
(3) Increase pressure to 337 25 PSI. Hold pressure to actuator for a period of five minutes. Any binding of
pistons is reason for rejection. Leakage, other than a slight wetting at seals insufficient to form a drop, is
reason for rejection.
(4) Increase applied pressure to 4500 PSI. Hold pressure to actuator for a period of two minutes. Actuator
pistons shall show no signs of distortion or permanent set. Leakage, other than a slight wetting at seals
insufficient to form a drop, is reason for rejection.
(5) Decrease pressure to 0 PSI. Open bleed valve slowly to bleed off remaining pressure. Brake disk test
segment should move freely between actuator assembly. Failure of disk segment to move freely is reason
for rejection.
(6) Close bleed valve. Torque valve to 40 INCH-POUNDS. Use torque wrench.
(7) Increase pressure to 80 +10/-0 PSI. Hold pressure to actuator for a period of five minutes.
(8) After two minutes, check for disk/lining clearance with thickness gage. Disk should have 0.060 0.030
INCH clearance each side. Remove disk segment from actuator. Failure of disk segment to move freely is
reason for rejection. Leakage, other than a slight wetting at seals insufficient to form a drop, is reason for
rejection.
(9) Decrease pressure to 0 PSI. Open bleed valve slowly to bleed off residual pressure remaining in actuator.
d. Perform dynamic leakage test.
(1) Insert brake disk test segment between friction lining of pistons.
(2) Close bleed valve. Torque valve to 40 INCH-POUNDS. Use torque wrench.
(3) Increase pressure to 337 25 PSI. Perform 25 cycles of application and release of pressure. Cycle rate
should not exceed two cycles per minute. Leakage at moving seals, other than a slight wetting at seals
insufficient to form a drop, is reason for rejection. Any binding of pistons is reason for rejection.
NOTE
Due to cylinder design, one piston normally leads in retraction. To confirm the opposing piston is not
mechanically binding, go to step (4). The relief of residual pressure through the bleed valve will permit
the piston to move to its upper limit and show that it is not mechanically binding.
(4) Decrease pressure to 0 PSI. Open bleed valve to bleed off residual pressure remaining in actuator.
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