4-9. GENERAL MAINTENANCE PROCEDURES - Continued
i. Oil Seals. Install oil seals with seal lip facing the source of oil. Install by carefully applying an even force on
the outer edge of the seal. If oil seals are to be installed over a keyed or splined shaft, use a guide.
This will prevent the sharp edges of the shaft damaging the lip seal. Make a guide by cutting and
shaping very thin gauge sheet metal over the splines. Make sure the edges are bent slightly inward
to prevent these damaging the seal.
j. Bearing Installation.
To prevent personal injury or premature bearing failure when
removing or installing bearing races, always exert force on the
tight ring of the bearing.
To assist in bearing installation procedures it is acceptable to heat or cool bearing races. Outer bearing
races can be cooled to reduce the race diameter. Place bearing in a deep freeze for about two hours
prior to assembly. It is acceptable to leave bearing in deep freeze for a longer period of time.
To avoid bearing failure, never heat a bearing using an open
flame. Inner bearing races can be heated to increase the race
An electrically-heated-type oil bath is recommended. Do not
allow oil temperature to exceed 275 deg. F (135 deg. C). The
preceding procedure can also be used to help during installation
of gears on shafts. If accessible, shafts may be cooled to reduce
outer diameter, and gears may be heated to increase inner
k. Lubrication. Lubricate bearings with the type of lubricant normally used before assembly (e.g., gear lube in
gear box bearing). This will provide lubrication during first run-in until system lubrication can reach bearings.