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 972 of 1015
3-215. DOUBLECHECK
TM 9-2320-272-24-1
THIS TASK COVERS:
a. Removal
b. Installation
APPLICABLE
MODELS
M931/A1/A2 and M932/A1/A2
TOOLS
General mechanic’s tool kit (Appendix E, Item 1)
MATERIALS/PARTS
Locknut (Appendix D, Item 291)
Antiseize tape (Appendix C, Item 72)
REFERENCES (TM)
TM 9-2320-272-10
TM 9-2320-272-24P
EQUIPMENT CONDITION
Air reservoirs drained (TM 9-2320-272-10).
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 primary relay valve control line (14) from valve adapter tee (13).
2.
Disconnect doublecheck valve No. 1 output line (11) from valve elbow (12).
3.
Disconnect secondary relay valve control line (10) from valve elbow (9).
4.
Disconnect doublecheck valve No. 2 control line (6) from bushing (5).
5.
Disconnect treadle valve control line (7) from valve adapter tee (8).
6.
Remove locknut (3), screw (1), and doublecheck valve No. 5 (4) from frame rail (2). Discard locknut (3).
NOTE
If new valve is being installed, use fittings from old valve.
Wrap all male pipe threads and wrap with antiseize tape before
installation.
1.
Position doublecheck valve No. 5 (4) against frame rail (2) and install with screw (1) and new locknut (3).
2.
Connect treadle valve control line (7) to valve adapter tee (8).
3.
Connect doublecheck valve No. 2 control line (6) to bushing (5).
4.
Connect secondary relay valve control line (10) to valve elbow (9).
5.
Connect doublecheck valve No. 1 output line (11) to valve elbow (12).
6.
Connect primary relay valve control line (14) to valve adapter tee (13).
3-608
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