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 970 of 1015
3-214. DOUBLECHECK
TM 9-2320-272-24-1
THIS TASK COVERS:
a. Removal
b. Installation
APPLICABLE MODELS
M931/A1/A2, M932/A1/A2
TOOLS
REFERENCES (TM)
TM 9-2320-272-10
TM 9-2320-272-24P
General mechanic’s tool kit (Appendix E, Item 1)
EQUIPMENT CONDITION
MATERIALS/PARTS
Parking brake set (TM 9-2320-272-10).
Air reservoirs drained (TM 9-2320-272-10).
Locknut (Appendix D, Item 299)
Antiseize tape (Appendix C, Item 72)
GENERAL SAFETY INSTRUCTIONS
Do not disconnect air lines before draining air
reservoirs.
Do not disconnect air lines before draining air reservoirs, Small
parts under pressure may shoot out with high velocity, causing
injury to personnel.
NOTE
Doublecheck valve No. 5 is used with airbrake kits on
M931/A1/A2 and M932/A1/A2 model vehicles. It is located inside
the left frame rail in back of the stoplight switch.
Tag air lines for installation.
1.
Disconnect two wires (6) from stoplight switch (5).
2.
Disconnect doublecheck valve No. 5 control line (8) from adapter tee (9).
3.
Disconnect protection valve control line (10) and trailer handbrake control line (7) from doublecheck
valve No. 2 (3).
4.
Remove locknut (2), screw (1), and doublecheck valve No. 2 (3) from left frame rail (4). Discard
locknut (2).
NOTE
If new doublecheck valve is being installed, use fittings from old
check valve.
Wrap all male pipe threads with antiseize tape before
installation.
1.
Position doublecheck valve No. 2 (3) against left frame rail (4) and install with screw (1) and new
locknut (2).
2.
Connect protection valve control line (10) and trailer handbrake control line (7) to doublecheck valve
No. 2 (3).
3.
Connect doublecheck valve No. 5 control line (8) to adapter tee (9).
4.
Connect two wires (6) to stoplight switch (5).
3-606
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