TM-9-2320-272-24-4
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 4 OF 4
JUNE 1998
TM-9-2320-272-24-4 - Page 70 of 836
TM 9-2320-272-24-4
5-10. PISTON AND CONNECTING ROD MAINTENANCE
THIS TASK COVERS:
a.
Connecting Rod Side Clearance Check
b. Removal
c.
Disassembly
d.
Cleaning and Inspection
e.
Assembly
f.
Installation
INITIAL SETUP:
APPLICABLE MODELS
M939/A1
SPECIAL TOOLS
Piston ring groove gauge (Appendix E, Item 97)
TOOLS
General mechanic’s tool kit (Appendix E, Item 1)
Torque wrench (Appendix E, Item 144)
Telescoping gauge (Appendix E, Item 136)
Outside micrometer (Appendix E, Item 80)
Inside micrometer (Appendix E, Item 82)
Piston ring expander (Appendix E, Item 96)
Arbor press
Feeler gauge
Soft-faced hammer
Vise
Tape-protected tool
a. Connecting Rod Side Clearance Check
1.
2.
3.
MATERIALS/PARTS
Twelve bearing shells (Appendix D, Item 14)
REFERENCES (TM)
TM 9-2320-272-24P
EQUIPMENT CONDITION
Camshaft and gear removed (para. 5-9).
GENERAL SAFETY INSTRUCTIONS
Gloves must be worn when handling hot pistons.
NOTE
Connecting rod should have free movement at crank journal.
Check with hand pressure first. Tap lightly with soft-faced
hammer only if necessary.
Move connecting rod (1) up and down on crank journal (3) and measure clearance with feeler gauge.
Clearance should be 0.0045-0.13 in. (0.11-0.33 mm). Record clearance of all six connecting rods for
reassembly.
NOTE
If clearance is not 0.0045-0.13 in. (0.11-0.33 mm) or rod will not
move, continue with steps 2 and 3.
Remove cap (2) and check for improper bearing size, dirt, or burrs.
Install cap (2) as outlined in task f.
5-64
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