TM-9-2320-272-24-3
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 3 OF 4
JUNE 1998
TM-9-2320-272-24-3 - Page 54 of 799
TM 9-2320-272-24-3
4-52. AIR COMPRESSOR MAINTENANCE (Contd)
b. Cleaning and Inspection
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
For general cleaning instructions, refer to para. 2-14.
For general inspection instructions, refer to para. 2-15.
Inspect compressor head (2) and compressor head cover (1) for cracks and breaks. If cracked or
broken, replace compressor head (2) or compressor head cover (1).
Inspect crankshaft (6) for scratches, scoring, and wear. Refer to table 4-6, Air Compressor Wear
Limits, for measurements. If damaged or worn, replace crankshaft (5).
Inspect bore (4) of support (3) for scratches, scoring, and wear. Refer to table 4-6, Air Compressor
Wear Limits, for measurements. If damaged or won, replace support (3).
Inspect thickness of thrust washer (10) for wear. Refer to table 4-6, Air compressor Wear Limits, for
measurements. If damaged or worn, replace thrust washer (10).
Inspect connecting rod (6), for breaks, bends, twists, scoring, and wear. If bent, broken, twisted,
scored, or worn, replace connecting rod (6).
Measure inside diameter of piston pin bore (7) and crankshaft journal (8). Refer to table 4-6, Air
Compressor Wear Limits, for measurements. If damaged or worn, replace connecting rod (6).
Measure outside diameter of piston pin (9). Refer to table 4-6, Air Compressor Wear Limits, for
measurements. If damaged or worn, replace piston pin (9).
Inspect piston (11) for breaks, cracks, scoring, and wear. If broken, cracked, scored, or worn, replace
piston (11).
Measure outside diameter of piston skirt (12). Refer to table 4-6, Air Compressor Wear Limits, for
measurements. If damaged or worn, replace piston (11).
Measure inside diameter of piston pin bore (13). Refer to table 4-6, Air Compressor Wear Limits. for
measurements. If damaged or worn, replace piston (11).
Table 4-6. Air Compressor Wear Limits.
ITEM NO.
ITEM/POINT OF MEASUREMENT
WEAR
LIMITS/TOLERANCES
INCHES
MILLIMETERS
4
Support bore/inside diameter
1.877
47.68
5
Crankshaft/outside diameter A
1.877
47.68
outside diameter B
1.933
49.10
outside diameter C
1.871
47.52
7
Piston pin bore/inside diameter
0.689
17.50
8
Crankshaft journal bore/inside diameter
1.935
49.15
9
Piston pin/outside diameter
0.687
17.45
10
Thrust washer thickness
0.240
6.10
12
Piston skirt/outside diameter
3.617
91.87
13
Piston pin bore/inside diameter
0.689
17.50
4-318
Back to Top
