TM-9-2320-272-24-4
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 4 OF 4
JUNE 1998
TM-9-2320-272-24-4 - Page 350 of 836
TM 9-2320-272-24-4
5-50. CENTER SUPPORT MAINTENANCE (Contd)
7.
Inspect all springs (6) for broken coils or coils distorted due to wear. If spring (6) is broken or
distorted, discard.
8.
Using spring tester, inspect all springs (6) for serviceability.
a. Compress spring (6) to 0.81 in. (20.7 mm) and check load.
b. If spring (6) does not give load of 4.30-5.70 lb (19.1.-25.4 N), discard.
d. Assembly
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
NOTE
Perform steps 1 and 2 only if bushing was removed.
Checkball will be installed when new bushing is pressed in.
Position checkball (2) in center support (3) and align notch on new bushing (1) with marked location
on center support (3).
Press new bushing (1) in center support (3) with bushing installer and arbor press until flush.
NOTE
The second and third clutch pistons are assembled the same way.
This procedure covers the second clutch piston.
Place second clutch piston (10) in center support (3).
Place twenty springs (6) in pockets on piston (11).
Align spring retainer (5) with pins (11) on piston (10) with retainer ring depth tool and install four
new self-locking retainer rings (4)
Remove second clutch piston (10) from center support (3).
Apply oil-soluble grease to new inner seal ring (8) and new outer seal ring (9).
Install new inner seal ring (8) and new outer seal ring (9) on second clutch piston (10). Ensure lips
of seal rings (8) and (9) face toward center support (3) when second clutch piston (10) is installed.
Repeat steps 3 through 8 to assemble third clutch piston (7).
NOTE
Do not install third clutch piston in center support at this time.
Install second clutch piston (11) in center support (3).
NOTE
Install new filter screen (13) and new seal ring (12) on center support (3).
5-344
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