TM 9-2320-280-34
This task covers:
a. Inspection
c. Checking Thickness Variation
b. Checking Lateral Runout
d. Refinishing
INITIAL SETUP:
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Too_
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Equi __ ent Condit on
General mechanic's tool kit:
Brake rotor removed (TM 9-2320-280-20).
automotive (Appendix G, Item 1)
Mai__enance_Level
___ nt _____ ____
Dial indicator (Appendix G, Item 95)
Direct support
Micrometer (Appendix G, Item 96)
__at__ial_/____s
M _ er__s Part _
Abrasive crocus cloth (Appendix B, Item 10)
Manual_R_fe__n_es
______ _e _ re_c _
TM 9-2320-280-20
TM 9-2320-280-24P
a. Inspection
NOTE
If rotor braking surfaces are rusted or scaled, they must be
cleaned before attempting inspection or measurement.
1.
Mount rotor (1) in brake lathe and turn while cleaning surfaces with abrasive crocus cloth.
2.
Inspect rotor (1) for heat cracks, nicks, broken cooling fins (2), scoring, discoloration, and pitting.
Replace if damaged.
b. Checking Lateral Runout
1.
Mount dial indicator with stylus contacting rotor (1) surface 1 in. (25 mm) in from outer edge.
2.
Turn rotor (1) 360 and note indicator reading.
3.
If lateral runout exceeds 0.004 in. (0.10 mm) total, replace or refinish rotor.
c. Checking Thickness Variation
1.
Measure thickness variation of rotor (1) with a micrometer at four equally-spaced points around
rotor (1). Measure 1 in. (25 mm) in from outer edge.
NOTE
Rotor must be replaced if minimum thickness falls below 0.81 in.
(20.6 mm). For the A2 and M1123 vehicles, rotor must be replaced
if minimum thickness falls below 0.97 in. (24.6 mm).
2.
If thickness variation exceeds 0.005 in. (0.13 mm), replace or refinish rotor (1).
d. Refinishing
1.
Mount rotor (1) on brake lathe and refinish surface.
2.
Replace rotor (1) if refinishing causes rotor (1) to fall below minimum thickness, 0.81 in. (20.6 mm)
or 0.97 in. (24.6 mm) for A2 and M1123 vehicles.
Change 1
