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 96 of 799
TM 9-2320-272-24-3
4-61. FAN DRIVE CLUTCH (M939/A1) MAINTENANCE
(Contd)
17.
Place clutch housing (1) on shaft (7) of clutch assembly bracket (6), install air adapter (4) on air
adapter fitting (3), and connect shop air hose (5). Do not apply air pressure at this time.
18.
Ensure clutch assembly bracket (6) and shaft (7) are firmly anchored to bench with clutch
housing (1) over shaft (7).
19.
Place shop towel or rag around shaft (7) to protect piston (2).
When working with compressed air, eyeshields must be worn.
Failure to wear eyeshields may result in injury to personnel.
Assistant will help with step 20.
20.
While assistant holds clutch housing (1) firmly in place, momentarily open shop air hose (5) and
apply 60 psi (414 kPa) to partially discharge piston (2). Ensure piston (2) discharges evenly. If
piston (2) discharges unevenly, press piston (2) back into clutch housing (1). Repeat discharge
action.
Extreme care must be used when removing piston from clutch
housing to avoid damaging piston. Do not use sharp tools, and do
not pry
or use force.
21.
Place clutch housing (1) on workbench with piston (2) side up.
22.
Insert two thin-bladed screwdrivers opposite each other and under lip above O-ring (9).
Assistant will help with step 23.
23.
Pulling evenly at several points around outside diameter of piston (2), remove piston (2) from clutch
housing (1).
24.
Remove O-rings (8) and (9) from piston (2). Discard O-rings (8) and (9).
25.
Remove seal plug (10) from clutch housing (1),
4-340
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