TM 9-2320-272-24-1
2-23. COMPRESSED AIR AND BRAKE SYSTEM TROUBLESHOOTING
a. This section contains troubleshooting information and tests for locating and correcting malfunctions
which may develop in the compressed air and brake system on vehicles covered in this manual. Each
symptom or malfunction given for an individual component or system is followed by step(s) you should take
to determine the cause and corrective action needed to remedy the problem. Compressed air and brake
system is divided into the following functional systems:
Parking Brake (page 2-179)
l
Service Brakes (page 2-180)
l
Compressed Air Supply (page 2-197)
l
Air-operated Accessories (page 2-213)
l
b. This troubleshooting guide is used to keep your vehicle operating and trouble-free as much as
possible in the quickest, easiest way.
(1) When a malfunction occurs, start at the source of the trouble and keep working back to
eliminate elements that are not defective to isolate the parts of the system that are. When found, this part,
line, or element is repaired, replaced, or otherwise corrected to get your vehicle running again.
(2) In the compressed air and brake system, emphasis in the troubleshooting guide is placed on
leaks, blockages in tubing and hoses, and correct pressure for operating various air-operated devices. Leaks
and blockages are easily determined using methods indicated in the tests.
(3) Correct air pressure requires a gauge of known accuracy, which is a special tool, to test
whether an element of the system is functioning or operating properly when supplied with the correct air
pressure.
c. Before taking any corrective action to correct a possible malfunction, the following rules should be
followed:
(1) Question operator to obtain any additional information that might help you to determine the
cause of the problem.
(2) Never overlook the chance the problem could be of a simple origin. The problem could require
only a minor adjustment.
(3) Use all senses to observe and locate troubles.
(4) Use test instruments and gauges to help you determine and isolate problems.
(5) Always isolate the system where the malfunction occurs and locate the defective component.
(6) Use standard automotive theories and principles when troubleshooting the vehicles covered in
this manual
(7) Operate the vehicle yourself to ensure the operator's description of the problem is correct.
(8) Always wear eyeshields when troubleshooting the compressed air system.
d. The compressed air schematic (Appendix H) shows the interrelationship of the compressed air and
brake system, and should be used as a reference when performing troubleshooting procedures. Table 2-4
lists malfunctions of the compressed air and brake system that may occur.
e . This section cannot list all compressed air and brake system malfunctions that may occur. If a
malfunction occurs that is not listed in table 2-4, notify DS maintenance.
WARNING
Do not disconnect air lines before draining air reservoirs. Small
l
parts under pressure may shoot out with high velocity, causing
injury to personnel.
Hearing protection is required for the driver and passenger.
l
Hearing protection is also required for all personnel working in
and around the vehicle while the engine is running. (Refer to
AR 40-5 and TB MED 501.)
2-177
