Mitsubishi 3000GT Service Manual page 39

WHEEL BEARING TROUBLESHOOTING
Trouble Symptom
Pitting Pitting occurs because of uneven rotation of race
and bearing surfaces
Flaking The surface peels because of uneven rotation of
the race and bearing surfaces
Cracking Chipping or cracking of cage or roller edges
Flat spotting When large load is applied, race and roller
contact surfaces compress, forming indentations
Nicks Instead of rolling along race surface, rollers slide,
thus damaging surface
Smearing Damage or wear caused by minute particles adher-
ing to surfaces results in rough movement and such
high temperatures that parts of surface melt
Rust, corrosion Appears on various areas of the bearing
Wear Wear of surface areas caused by friction
Grease discoloration results from grease deteriora-
Discoloration
tion which causes particles of pigment contained in
grease to adhere to surfaces
Heat discoloration will appear as a deep brown or
GENERAL - Master Troubleshootina
Probable cause
Excessive bearing preload
Excessive load
End of bearing life
Improper bearing assembly
Impact when bearing was installed
(such as being hit with a hammer)
Excessive bearing preload
Excessive load
Vibration when bearings are not used,
such as during shipment on freight
cars, transport trucks, etc.
Insufficient grease
Excessive bearing preload
Excessive load
Faulty oil seal
Excessive variation of loads on
bearings
Use of grease other than that specified
lnsuff icient grease
Use of grease otherthan that specified
Faulty oil seal
Presence of water or moisture
Insufficient grease
Foreign matter
Rust or corrosion due to moisture
Use of grease other than that specified
Faulty oil seal
Use of grease other than that specified
Faulty oil seal
Excessive bearing preload
Excessive load