MAINTENANCE OF M939 SERIES VEHICLE - OD1661 - LESSON 1/PE 1
LESSON 1.
PRACTICAL EXERCISE - ANSWERS
1.
Requirement
a.
The M939 series vehicle are designated as 5 ton, 6x6.
b.
The purpose of the M923 and M925 is to transport payloads up to
20,000 pounds on the highway and 10,000 pounds cross-country. Fully
loaded, each will tow an additional trailer load up to 30,000 pounds
on the highway and 15,000 pounds cross-country.
c.
The load limits for the M929 and M930 dump trucks are 20,000
pounds on the highway and 10,000 pounds cross-country.
d.
The normal operating temperature range for the engine in the
M939 is 175 F to 195 F.
e.
The two functions of the wet tank reservoir are:
1) Traps water in the air to protect other air systems from
freezing or corrosive damage.
2) Stores air enabling the operator to make normal stops when the
engine stalls or the compressor fails.
f.
The normal air pressure for the primary air system is between 90
and 130 psi.
g.
The general rules of troubleshooting are:
1) Question the vehicle operator to obtain any information that
might help determine the cause of the maintenance problem.
2) Never overlook the chance that the maintenance problem could
be of simple origin.
The problem could be corrected with minor
adjustment.
3) Use all senses to observe and locate troubles.
4) Use test instruments or gages to help determine and isolate
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