Chevrolet Light Duty Truck 1973, Руководство по обслуживанию

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4-22 REAR SUSPENSION AND DRIVELINE
mishandling in storage and installation. They are
adversely affected by dirt and they should be protected
from rust and corrosion.
Bearings are carefully assembled, washed, dried and
either lubricated or treated with a rust preventative at
the factory. They are then packaged for protection and
shipped to a distributor or to the ultimate user.
Bearings should not be removed from the original
packaging until they are ready for installation. When a
bearing is shipped from the factory it is ready for
installation. No cleaning or washing is recommended.
Field washing of new bearings, prior to installation,
seldom improves on the factory cleaning and could
impair the original cleanliness of the bearing.
Once a bearing has been removed from the original
packing, care must be exercised to prevent damage from
dirt and corrosion. Many bearing failures are the result
of improper handling, careless installation, misuse or
abuse rather than actual wear or fatigue in service.
The useful life expectancy of bearings can be greatly
extended if proper installation and maintenance
practices are observed.
Removal Procedures
Regardless of the means used to remove bearings or
races, it is absolutely essential that the driving force be
directed through the
press fitted race.
For example, if a
non-separable bearing is to be removed from a shaft, the
force must travel through the inner race and never
through the outer race, rollers or separator.
In most applications, it will be found that the roller
bearing has been assembled with a tight press fit holding
the rotating race, and with a relatively free fit holding
the stationary race. Removing the race with the free fit
can be done quite easily, but the race with the tight press
fit will require considerable force, which must be applied
in such a way that the bearings and component parts are
not damaged.
The Arbor Press.
The arbor press is one means of
applying the force necessary to remove bearings or races
from shafts and housings. Its action is rapid, smooth and
positive, making it an especially useful tool where a
great deal of bearing removal work is done. In addition,
the arbor press can supply a greater force than is
available from most other bearing removal appliances,
making it possible to remove some bearings which might
not even be budged by bearing pullers or by hammering.
With the arbor press, the bearing is supported on the
press base plate with some simple accessories. These may
consist of flat bars placed beneath the inner race
adjacent to the shaft. A piece of flat stock with a
U-shaped cutout is preferable when this operation has to
be repeated often. A third type of accessory is the split
ring, a circular ring bored slightly larger than the shaft
diameter and sawed into two semi-circular segments.
The arbor press can only be used to remove races or
bearings from housings which are so designed that some
portion of the outer race can be exposed. In cases where
the entire face of the outer race is exposed, a section of
pipe or tubing, capped by a steel block, can be used. In
other cases, the shoulders against which the outer races
rest are slotted to allow a flat bar to contact the outer
race in two diagonally opposite places. The important
thing to remember in any of these operations is that the
force should only be directed through the
press-fitted
race,
and that the press base plate and accessories are
clean, and that all contacting surfaces are flat and true.
Bearing Pullers.
Bearing pullers are a useful and
convenient means of removing bearings and races, where
no arbor press is available, or where the shaft is too
large or is obstructed and cannot go into a press.
The bearing puller must be applied so that the pressure
is directed through the press-fitted race, and that no
force is carried through the rollers or snap rings. The
puller can be used without accessories to draw off inner
races where no obstructions interfere and where long
reach is not necessary. In most cases, the split collar
puller plate is placed in back of the bearing to carry the
load directly to the inner race. In some applications, a
gear, pulley or cover plate can be used instead of the
split collar. When bearing pullers having adjustable legs
are used, it is important that the legs be of equal length
and symmetrically placed.
Cleaning of Used Bearings
Bearings which have been removed from service should
be cleaned before storing, even when the storage is to be
only of short duration. The bearing should be cleaned
thoroughly, removing all oil and hardened grease
accumulations, as well as any sludge which may be
deposited on the outer surfaces of the races. Remember
that cleaning of bearings is important and, whenever
possible, should be done before relubricating bearings.
Bearings can be cleaned easier and more thoroughly
when they have been removed from their housings and
shafts. When this is not possible, a light oil heated at
LIGHT DUTY TRUCK SERVICE MANUAL