TM-9-2320-272-23-3

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 3 OF 5

SEPTEMBER 2012
TM-9-2320-272-23-3

  TM-9-2320-272-23-3 - Page 1075 of 1469

REAR HUB LEAK TEST
NOTE
Air seals may not retain prescribed pressure immediately after installation. Pressure will be
maintained after seals have been in operation and have seated on spindle.
1.
Install washer (Figure 2, Item 6), o-ring (Figure 2, Item 5), and rear hub connector (Figure 2, Item 4) on hub
(Figure 2, Item 7).
2.
Install plug (Figure 2, Item 3) on rear hub connector (Figure 2, Item 4).
3.
Disconnect hose (Figure 2, Item 2) from quick-exhaust valve elbow (Figure 2, Item 1) and install pressure
gauge on hose.
WARNING
Eyeshields must be worn when cleaning with compressed air. Compressed air source will
not exceed 30 psi (207 kPa). Failure to comply may result in injury or death to personnel.
CAUTION
Ensure external air source is known to be as clean and dry as air supplied by vehicle. If in
doubt, use the vehicle's air supply. Contamination may cause damage to CTIS.
4.
Apply air pressure to rear hub (Figure 2, Item 7) until air pressure gauge (Figure 2, Item 8) reads 80 psi
(552
kPa).
5.
Observe air pressure gauge (Figure 2, Item 8) for one minute. Pressure gauge should not drop below 70 psi
(483 kPa). If air dropped below 70 psi (483 kPa), check connections for leaks using soapsud method.
6.
If connections are tight, replace hub air seals (WP
0481) or (WP
0482).
WARNING
Air pressure may create airborne debris. Use eye protection. Failure to comply may result in
injury or death to personnel.
7.
If air pressure remained at 70 psi (483 kPa) or above, release air pressure through valve on air pressure gauge
(Figure 2, Item 8).
NOTE
Wrap all male threads with antiseize tape before installation.
8.
Remove air pressure gauge (Figure 2, Item 8) from hose (Figure 2, Item 2), and connect hose to quick-exhaust
valve elbow (Figure 2, Item 1).
9.
Remove plug (Figure 2, Item 3) from rear hub connector (Figure 2, Item 4).
10.
Remove rear hub connector (Figure 2, Item 4), o-ring (Figure 2, Item 5), and washer (Figure 2, Item 6) from
hub (Figure 2, Item 7).
TM 9-2320-272-23-3
0487
0487-4


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