TM 9-2320-272-24-4
5-8. CRANKSHAFT AND MAIN BEARINGS MAINTENANCE
THIS TASK COVERS:
c. Installation
a. Removal
d. End Play Clearance
b. Cleaning and Inspection
INITIAL SETUP:
REFERENCES (TM)
APPLICABLE MODELS
TM 9-2320-272-24P
M939/A1
EQUIPMENT CONDITION
TOOLS
Connecting rod and pistons removed (para. 5-10).
General mechanic's tool kit (Appendix E, Item 1)
Main bearing cap puller (Appendix E, Item 108)
GENERAL SAFETY INSTRUCTIONS
Outside micrometer (Appendix E, Item 80)
l Keep fire extinguisher nearby when using
Vernier caliper (Appendix E, Item 159)
drycleaning solvent.
Torque wrench (Appendix E, Item 144)
l Drycleaning solvent is flammable and toxic. Do
Dial indicator (Appendix E, Item 36)
not use near an open flame.
Hoist
l When cleaning with compressed air, wear
Rubber-protected hooks
eyeshields and ensure source pressure does not
MATERIALS/PARTS
exceed 30 psi (207 kPa).
Crankshaft main bearing set
Thrust ring set (Appendix D, Item 682)
Fourteen lockplates (Appendix D, Item 341)
Woodruff Key (Appendix D, Item 738)
Fourteen dowel rings (Appendix D, Item 100)
Lint-free cloth (Appendix C, Item 21)
GAA grease (Appendix C, Item 28)
Lubricating oil (Appendix C, Item 50)
Drycleaning solvent (Appendix C, Item 71)
a. Removal
1.
Turn engine block (1) upside down.
2.
Bend down lockplate tab (8) and remove two screws (7) from seven main bearing caps (9). Discard
lockplates (8).
NOTE
Tag all bearing caps and bearing shells for installation.
3.
Remove main bearing caps (9) from engine block (1) with main bearing cap puller.
4.
Remove lower half bearing shell (10) from main bearing caps (9). Discard lower half bearing shell (10).
5.
Remove lower half of thrust ring (4) from crankshaft near journal (5). Discard thrust ring (4).
6.
Carefully remove crankshaft (6) from engine block (1) using hoist and rubber-protected hooks (11).
Place crankshaft (6) on clean, flat surface.
7.
Remove upper half bearing shells (2) from engine block (6). Discard upper half bearing shells (2).
8.
Remove fourteen dowel rings (3) from engine block (1). Discard dowel rings (3).
9.
Remove upper half of thrust ring (4) from engine block (1). Discard thrust ring (4).
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