TM-9-2320-272-24-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4
JUNE 1998
TM-9-2320-272-24-1 - Page 868 of 1015
TM 9-2320-272-24-1
3-181. SERVICE BRAKE CHAMBER REPLACEMENT
THIS TASK COVERS:
a. Removal
b. Installation
INITIAL SETUP:
APPLICABLE MODELS
All
TOOLS
EQUIPMENT CONDITlON
Parking brake set (TM 9-2320-272-10).
Air reservoirs drained (TM 9-2320-272-10).
Wheel brakedrum dustcovers removed
General mechanic’s tool kit (Appendix E, Item 1)
(para. 3-178).
MATERIALS/PARTS
GENERAL SAFETY INSTRUCTIONS
Antiseize tape (Appendix C, Item 72)
Do not disconnect air lines before draining air
REFERENCES (TM)
TM 9-2320-272-10
TM 9-2320-272-24P
reservoirs.
Do not disconnect air lines before draining air reservoirs. Small
parts under pressure may shoot out with high velocity, causing
injury to personnel.
Tag all lines for installation.
1.
Disconnect service brake control line (6) from brake adapter (7).
2.
Remove brake adapter (7) from service brake chamber (3).
3.
Disconnect vent line (5) from elbow (4).
4.
Remove elbow (4) from service brake chamber (3).
Perform step 5 for rear service brake only.
5.
Remove two nuts (9), washers (10), U-bolt (12), and clamp (11) from service brake chamber (3).
6.
Loosen collet nut (2) and remove service brake chamber (3) from actuator housing (8). Record
position for installation.
7.
Remove collet nut (2) from service brake chamber (3).
Wrap all male pipe threads with antiseize tape before installation.
1.
Install collet nut (2) on brake chamber (3).
2.
Ensuring collet nut (2) is loose, install brake chamber (3) over wedge assembly (1) and into actuator
housing (8), with brake chamber (3) positioned for air line connection. Thread collet nut (2) to
bottom of brake chamber (3) and tighten 3/16 in. (4.8 mm) or 1-1/2 teeth.
3-504
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