| |
TM 10-3930-660-34
3-9. CRANKSHAFT MAIN BEARINGS - REPLACE (Cont’d)
g.
Repeat STEPS a through f for remaining
main bearings 2 through 5 and thrust
bearing (5) at main bearing position 6.
CLEANING
CAUTION
Never use any type of rough material or
tools such as sandpaper, emery or crocus
cloth, files, or glassbead cleaning equipment
to clean bearings.
1.
SEE CLEANING INSTRUCTIONS, PARA. 2-10.
2.
APPLY A LIGHT COAT OF OIL OVER THE
BEARINGS AND THE BEARING SURFACE IN THE
BEARING CAPS IF THE BEARINGS ARE NOT
GOING TO BE INSTALLED WITHIN ONE HOUR
AFTER CLEANING.
INSPECTION
1.
INSPECT MAIN BEARINGS AND THRUST
BEARING. REPLACE BEARING IF:
·
back of bearing shows that fretting has taken
place,
·
back of bearing has a mirror-like (shiny) finish,
·
there are scratches in the bearing surface which
do not disappear after cleaning,
·
bearing surface has material damage such as
cracks or flaking,
·
there is a hole in the bearing surface,
·
bearing shows wear on the mating face,
·
bearing oil hole is distorted,
·
there are hot spots in bearing surface, and/or
·
bearing has damage to the tab.
2.
INSPECT THRUST BEARING FLANGES FOR
DAMAGE. IF DAMAGED, REPLACE THRUST
BEARING.
3.
INSPECT MAIN BEARING BORES IN THE
BLOCK FOR CRACKS, CHIPS, DISTORTION,
THREAD DAMAGE, OR OTHER DAMAGE.
REPLACE CYLINDER BLOCK IF THERE IS
BEARING BORE DAMAGE.
4.
INSPECT
AND
MEASURE
CRANKSHAFT
MAIN BEARING JOURNALS, PARA. 3-8.
5.
INSPECT
MAIN
BEARING
CAPS
FOR
CRACKS, FRETTED OR CHIPPED MATING
SURFACES, DISTORTION, OR
DAMAGED
RING DOWELS.
a.
Replace a damaged bearing cap.
b.
Replace both bearing cap ring dowels if one
or both are damaged.
INSTALLATION
1.
INSTALL MAIN BEARINGS 2 THROUGH 6 (3
AND 4) FOR MAIN BEARING CLEARANCE CHECKS.
a.
If main bearings are coated with oil, remove
oil with a clean wiping rag.
CAUTION
To help prevent damage to the cylinder
block during main bearing bore cleaning,
compressed air shall not exceed 15 psig.
Use compressed air only with effective chip
guarding and personal protective equipment.
3-69
|