Vaz 21213, Руководство по ремонту, Страница: 95 / 222

driven gear teeth the contact pattern is located in regular intervals
closer to the narrow end of the tooth, occupying two thirds of
length and without covering the top and the base of the tooth, as
shown on fig. 3-80, e.
The examples of wrong location of contact pattern on the
tooth working surface are shown on fig. 3-80 (a, b, c, d).
The unit will have to be dismantled to make the adjustments
of the driving gear and replace the adjusting ring.
After reassembly, repeat all operations on the driving gear
roller bearings preload, check the moment of resistance to rota-
tion, the preload of the differential housing roller bearings and the
adjustment of the final drive mesh side gap.
Replacing the driving gear sealing
The necessity of seal replacement is determined by the drop
of oil level in the rear axle casing (due to oil leak through the sea-
ling) to the level which might affect normal operation of the reduc-
tion gear.
Misting of the casing filler neck and even oil drops, in the
amount not exceeding the below norms, do not indicate oil leak.
In case of heavy drop formation inspect the sealing:
- put the vehicle on the lift or over an inspection pit;
- clean the breather from dirt and inspect;
- undo the control plug, check the oil level in the axle casing;
top up if necessary;
- clean the casing filler neck from oil and wipe dry;
- raise the rear axle and put it on supports;
- start the engine, engage the fourth gear and at speed of 90-
100 km/h warm oil up to 80-90 °ë (approximately during 15 min-
utes);
-with the fourth gear engaged, at speed of 100 km/h deter-
mine the amount of oil leakage during 15 minutes.
Oil leak exceeding 5 drops in 15 minutes will indicate a bad
sealing.
Damaged sealing can be replaced without removing the
reduction gear from the vehicle, if no replacement of other parts
of the reduction gear is required.
The procedure of seal replacement is the following:
- drain oil from the rear axle casing;
- loosen the rear wheels fastening nuts, put blocks under front
wheels and raise the rear axle; release the handbrake and place
the gear shift lever in neutral;
- take off the wheels and brake drums;
- undo the nuts that are fastening the braking plate to the axle
beam and using a pusher remove the axle shafts from the differ-
ential box;
- disconnect the propeller shaft from the driving gear flange
and move the shaft aside;
- using a dynamometer check the driving gear moment of
resistance to rotation and note;
- hold the flange with a special key, undo the driving gear
flange fastening nut and remove the flange with the washer;
- remove the driving gear sealing;
- grease the seal working surface with ãàíéã-24 and press
fit with a mandrel into the reduction gear casing on depth of 2-0.3
mm between the end face of the reduction gear casing and the
sealing outer surface;
- fit the flange with a washer on the driving gear, hold it with
a special key and tighten the flange fastening nut, controlling the
moment of resistance to rotation by a dynamometer from time to
time.
If the initial value of moment of resistance to rotation was 58.8
N•cm (6 kgf•cm) or more, the new one should exceed the initial
by 9.8-19.6 N•cm (1-2 kgf•cm). If the initial moment of resistance
to rotation was less than 58.8 N•cm (6 kgf•cm), the flange fas-
tening nut should be tightened to 58.8-88.2 N•cm (6-9 kgf•cm).
If the moment of resistance to rotation was exceeded when
tightening the nut, dismantle the reduction gear, renew the dis-
tance sleeve, then reassemble the reduction gear and adjust as
described in chapter "Assembly and adjustment".
The reassembly of the rear axle is carried out in sequence
reverse to dismantle.
95
Fig. 3-80. Bearing pattern in final drive gear mesh:
I - front side; II - rear side; «a» and «b» - improper contact in gear mesh: move
the drive gear away from the driven gear by reducing the shim thickness; «c»
and «d» - improper contact, move the drive gear closer to the driven by increas-
ing the shim thickness; «e» - right contact in gear mesh