TM-9-2520-238-34
M113A1 FOV, M113A2 FOV, M548 AND M548A1
TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL; RIGHT ANGLE DRIVE, COOLING FAN; GEARCASE, TRANSFER; DRIVE ASSEMBLY, FINAL; DIFFERENTIAL, STEERING CONTROL; BRAKE, SINGLE DISK; CYLINDER ASSEMBLY, HYDRAULIC BRAKE
TM-9-2520-238-34 - Page 30 of 319
TM 9-2520-238-34
INTRODUCTION TO HOW TO USE TROUBLESHOOTING
0004 00
PURPOSE
The purpose of direct and general support maintenance level troubleshooting is to diagnose carrier problems which are
reported to direct and general support maintenance. Troubleshooting tasks in this manual are common to all M113 FOV
carriers except where indicated. You should not begin direct and general support maintenance troubleshooting until all
operator and unit troubleshooting procedures have been completed. You will perform four actions in direct and general
support maintenance troubleshooting:
(1) Before starting a troubleshooting task, verify that the reported problem is present in the carrier.
(2) After verifying the symptom, find the part that is causing the problem.
(3) Replace or adjust that part.
(4) Check to make sure the problem no longer exists, and that there are no other problems.
DEFINITIONS AND DESCRIPTIONS OF TROUBLESHOOTING PROCEDURES
Troubleshooting tasks always have a beginning and an end. You will use task steps, test procedures, indexes, maintenance
tasks, and other technical manuals to troubleshoot. Troubleshooting uses the following terms that are not used in other kinds
of tasks:
1. FAULT:
The part that is not operating correctly and is causing the problem.
2. SYMPTOM:
The problem reported to direct and general support maintenance.
3. VERIFY NO FAULTS
FOUND:
After you have completed the corrective action, you must verify that no faults exist.
If the fault condition still exists, then the fault is not fixed or there is another fault.
If this happens, start at the beginning of the troubleshooting procedure until you
find and correct all faults. Always operate the system and/or carrier to make sure
that you have corrected the reported problem. If troubleshooting does not identify a
faulty part, the carrier is defective beyond the level of direct and general support
maintenance.
TROUBLESHOOTING BASICS
Troubleshooting Procedure
A troubleshooting procedure serves as a starting point for your troubleshooting work. You will branch in and out of
procedures as you work to find a fault. Also, you will correct the fault, and check that the fault has been corrected. The parts
of a troubleshooting procedure are given below.
TM 9-2520-238-34
DIFFERENTIAL MAKES EXCESSIVE NOISE OR VIBRATES WHILE MOVING
0010 00
INITIAL SETUP:
Maintenance Level
Direct/General Support
Tools and Special Tools
General mechanic’s tool kit (WP 0034 00, Item 37)
Personnel Required
Track Vehicle Repairer
References
See your-20
Equipment Condition
Differential removed from carrier (See your -20)
Disassemble for inspection per repair differential right
angle gearbox (WP 0029 00)
Repair output shaft assemblies (WP 0025 00)
T
TN
NO
NO
YN
Y
YES
1. Inspect bevel gear backlash to see if it has been adjusted.
2. Has bevel gear backlash been adjusted?
1. Inspect shaft gear bearing to see if it has been adjusted.
2. Has shaft gear bearing been adjusted?
1. Adjust bevel gear backlash
(WP 0029 00).
2. Verify no faults found.
1. Adjust shaft gear bearing
(WP 0029 00).
2. Verify no faults found.
0004 00-1
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