2.26. Adjustment and replacement of bearings of back wheels

Check
On the car lifted and reliably fixed on supports quickly turn back wheels and check lack of noise in bearings, resistance to turn and a side play. Take a back wheel hands in situation "6 hours" and try to shake it in the vertical plane, at the same time the admissible side play makes no more than 0,5 mm. If a side play big, it is necessary to check and adjust or replace wheel bearings.
Service of bearings of forward wheels requires dismantling of a forward nave, bearings of back wheels can be replaced at the current maintenance.

Replacement
Lift a back part of the car and fix on supports.
Remove wheels and lower the lever of the parking brake.
By means of a chisel and the hammer remove a dustproof cap of a nave, tapping it around until it is displaced and it it is possible to remove.
Unbend a fillet and turn off a nut of fastening of a nave. At installation it is necessary to use a new nut.
Extend the nave block a little outside and then establish in initial situation.
This operation has to push forward the external bearing and a washer on an axis so that they can be removed fingers.
Remove a nave, establish it on a suitable working surface and the screw-driver remove an internal ring of the bearing.
Remove with solvent all remains of old lubricant from bearings, a nave and an axis. For this purpose it is possible to use a small brush, at the same time be careful that bristles from a brush did not get in basic rollers. Dry up details by means of a stream of compressed air.
Carefully examine bearings on lack of cracks, development and uneven wear. Bearings and rings is a uniform set therefore new rings demand installation of new bearings. Similarly when replacing bearings in a nave establish new rings.
For filling of bearings use high-temperature lubricant which is filled between rollers, the conical surface and the case of the bearing.
Apply a thin film of lubricant on an axis, the external and internal surfaces of the bearing, the lever and laying.
Press a small amount of lubricant in each bearing in a nave. A finger of a hand create a layer in these points to provide additional lubricant and to hold a thin layer of lubricant from an effluence from the bearing.
Install the internal bearing filled with lubricant in a nave and add a little lubricant from the outer side of the bearing.
Establish from above the internal bearing new laying which open ledge is directed to the bearing, and evenly press laying into place.
Grease a laying ledge, install the nave block on an axis and install into place the external bearing filled with lubricant and laying.
Screw a new nut on an axis and adjust preliminary loading of the bearing as follows:
– tighten a nut the initial moment specified in specifications;
– turn a nave two-three times for installation of rollers of bearings, then weaken a nut on one turn, at the same time be convinced that brakes do not move;

Fig. 2.19. Measurement of preliminary loading of the bearing of a back wheel by means of a spring dynamometer


– attach a spring dynamometer to the top hairpin of fastening of a wheel and measure the moment at which the nave begins to turn (this size determines resistance of oil consolidation) (fig. 2.19);
– tighten a nut until resistance (a point at which the nave begins to turn) does not become 3,9-9,8 N more, than consolidation resistance;
– hammer with the hammer and a core a nut fillet into an axis groove.
Fill a dustproof cap with lubricant and establish it by means of the hammer and a core.
Establish wheels and lower the car on the earth. Tighten nuts of fastening of wheels.
Several times press a brake pedal to modify the provision of brake shoes, then check the course of the lever of the parking brake and adjust it in case of need.