PARKING BRAKE MASTER CYLINDER DISASSEMBLY/ASSEMBLY (AVIM) continued
a. Check master cylinder and its components for cracks, nicks, or dents (para 3.53).
b. Magnetically examine pistons for cracks (TM 55-1500-335-23).
c. Check master cylinder and its components for excessive wear. None allowed.
d. Check rod, cap, pistons, and cylinder for damaged threads. None allowed.
e. Check cylinder and its components for corrosion (para 1.49).
f. Check seating surfaces of pistons and seat for sharp edges or burrs. None allowed.
g. Check rod end and cylinder brake cap bearings for free movement and smooth operation (para 3.53).
h. Check springs for discoloration, misalinement, permanent set, and distortion.
(1) Roll springs on smooth flat surface. No wobble allowed.
(2) Measure free length. Poppet spring free length shall be 0.666 to 0.688 INCH. Cylinder brake spring free
length shall be 4.17 to 4.23 INCHES. Use spring tester.
(3) Measure compressed length. Poppet spring compressed length shall be 0.578 INCH under a 3.3 to 3.6
POUND test load. Piston spring compressed length shall be 3.2 INCHES under an 11.6 to 12.0 POUND
test load. Use spring tester.
i. Check piston screen for damage, contamination, or clogging.
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