scratching. Curling under of any seal lip will seriously impair its efficiency. Apply a thin coat of Loctite
#120 to outer diameter, of metal casing, on oil seals to assure an oil tight fit into retainer. Use extreme
care not to get Loctite on lips of oil seals. If this happens, that portion of the seal will become brittle and
allow leakage.
When replacing lip type seals, make sure spring loaded side is towards oil to be sealed.
5. If available, use magna-flux or similar process for checking for cracks that are not visible to the eye.
Examine teeth on all gears carefully for wear, pitting, chipping, nicks, cracks or scores. Replace all
gears showing cracks or spots where case hardening has worn through. Small nicks may be removed
with suitable hone. Inspect shafts and quills to make certain they have not been sprung, bent, or
splines twisted and that shafts are true.
NOTE: Spline wear is not considered detrimental except where it affects tightness of splined parts.
Inspect thrust washers for distortion, scores, burs, and wear. Replace thrust washer if defective or
worn.
6. Inspect bores and bearing surfaces of cast parts and machined surfaces for scratches, wear, grooves
and dirt. Remove any scratches and burrs with crocus cloth. Remove foreign material. Replace any
parts that are deeply grooved or scratched which would affect their operation.
BEARING INSPECTION
The conditions of the bearing are vital to the smooth and efficient operation of the machinery. When any
component containing bearings is disassembled, always carefully examine the condition of the bearings and
all of its components for wear and damage.
Once the bearing is removed, clean all parts thoroughly using a suitable cleaning solution. If the bearing is
excessively dirty soak the bearing assembly in a light solution and move the bearing around until all
lubricants and or foreign materials are dissolved and the parts are thoroughly clean.
When drying bearings, moisture free compressed air can be used. Be careful not to direct the air in a
direction which will force the bearing to dry spin while not being properly lubricated.
After the bearings have been cleaned and dried, carefully inspect all bearing rollers, cages and cups for wear,
chipping or nicks. If the bearing cannot be removed and is to be inspected in place, check foe roughness of
rotation, scoring, pitting, cracked or chipped races. If any of these defects are found replace the whole
bearing assembly. NEVER replace the bearing alone without replacing the mating cup or the cone at the
same time.
After inspection lightly coat the bearing and related parts with oil and wrap in a clean lintless cloth or paper
and protect them from moisture and other foreign materials until installation.
It is also important to inspect the bearing housing and/or shaft for grooved, galled or burred conditions that
indicate that the bearing has been turning in its housing or on its shaft.
If available, use magna-flux or similar process for checking for cracks that are not visible to the naked eye.
The following illustrations will aid in identifying and diagnosing some of the bearing related problems.
NOTE: The illustrations will only show tapered roller bearings, but the principles of identifying,
diagnosing and remedying the defects are common to all styles and types of bearings.
S0302000 General Maintenance Procedures
Page 8
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