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 1073 of 1469

FRONT 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 o-ring (Figure 1, Item 5) and air manifold (Figure 1, Item 6) on drive flange (Figure 1, Item 4) with washer
(Figure 1, Item 11) and screw (Figure 1, Item 10).
2.
Install short end of spacer (Figure 1, Item 9) on air manifold (Figure 1, Item 6) with washer (Figure 1, Item 8)
and screw (Figure 1, Item 7).
3.
Install plug (Figure 1, Item 12) on air manifold (Figure 1, Item 6).
4.
Remove hose (Figure 1, Item 3) from bulkhead fitting (Figure 1, Item 2) and install air pressure gauge
(Figure
1, Item 1) 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 know 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.
5.
Apply air pressure to front hub until air pressure gauge (Figure 1, Item 1) reads 80 psi (552 kPa).
6.
Observe air pressure gauge (Figure 1, Item 1) for one minute. Pressure should not drop below 70 psi
(483
kPa). If air pressure dropped below 70 psi (483 kPa), check connections using soapsud method.
7.
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.
8.
If air pressure remained at 70 psi (483 kPa) or above, release air pressure through valve on air pressure gauge
(Figure 1, Item 1).
9.
Remove air pressure gauge (Figure 1, Item 1) from hose (Figure 1, Item 3) and connect hose to bulkhead
fitting (Figure 1, Item 2).
TM 9-2320-272-23-3
0487
0487-2


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