I”! 1: 1’ --- -~~
30 INTRODUCTION AND MASTER TROUBLESHOOTING
- Master Troubleshooting
WHEEL BEARING TROUBLESHOOTING
Trouble Symptom
Probable cause
Pitting
Flaking
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
?ust, corrosion
Near
Xscoioration Pitting occurs because of uneven rotation of race
and bearing surfaces
The surface peels because of uneven rotation of
the race and bearing surfaces
Instead of rolling along race surface,
rollers slide, thus damaging surface
Damage or wear caused by minute particles
adhering to surfaces results in rough movement
and such high temperatures that parts of surface
melt
Appears on various areas of the bearing
Wear of surface areas caused by friction
Grease discoloration results from grease
deterioration which causes particles of pigment
contained in grease to adhere to surfaces
Heat discoloration will appear as a deep brown or
purple 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.
Improper grease
Excessive bearing preload
Excessive load
Faulty oil seal
Excessive variation of loads on
bearings
Use of grease other than that
specified
Improper grease
Use of grease otherthan
that specified
Faulty oil seal
Presence of water or moisture
Improper grease
Foreign matter
Rust or corrosion due to
moisture
Use of grease otherthan that
specified
Faulty oil eal
Use of grease other than
that specified
Faulty oil seal
Excessive bearing preload
Excessive load
