Regularly check the tightening of the bolts securing the final drive to the axle housing. Loosening the bolts causes the housing to bend.
When adjusting the final drive, adjust the preload of the tapered bearings and check the contact pattern in the mesh of the bevel pair of final drive gears.
Perform adjustment work with the final drive removed from the vehicle.
Control the amount of tension by the torque required to rotate the shaft. Determine the moment of resistance to turning using a dynamometer.
It is necessary to measure the torque on the shaft when turning it smoothly in one direction and after at least five full revolutions.
It should be borne in mind that incorrect adjustment of the bearings can lead to the destruction of not only the bearings themselves, but also the final drive gears.
Adjust the final drive in the following sequence:
Install the final drive into the fixture, remove the differential and flanges.
Unscrew the bolts securing the bearing cup of the drive bevel gear. Remove the drive gear shaft with the cup and gear.
Install the drive gear in a vice, holding it by the ring gear.
Unscrew the cover bolts and remove it.
Unlock the lock nut and unscrew it.
Remove the lock washer and the lock washer. Tighten the nut to a torque of 450–500 N·m (45–50 kgf·m).
Install the indicator device and determine the clearance in the bearings.
If there is no clearance after tightening the nut, there is no need to adjust the cup bearings.
Calculate the amount of reduction in the thickness of the adjusting washer 24 (see Fig. 1) (the amount of the clearance plus 0.03–0.05 mm of preload).
Unscrew the nut, remove the bearing and adjusting washer.
Grind (or select) the washer to the required size, install the washer and assemble the drive bevel gear bearing assembly. The nut tightening torque is 450–500 N·m (45–50 kgf·m).
Secure the lock nut by bending the washer onto one of the edges.
The torque required to rotate the drive bevel gear in the bearings should be 0.6–1.4 N·m (0.06–0.14 kgf·m).
The force on the dynamometer when unwinding the cord from the surface of the cup is 7.5–17.5 N (0.75–1.75 kgf) (Fig. 2).
Adjust the preload of the intermediate shaft bearings. Adjust the bearings by selecting a pack of shims 8 (see Fig. 1) under the cover 9 of the cup 5.
The torque required to rotate the intermediate shaft should be 0.9–1.5 N·m (0.09–0.15 kgf·m).
When measuring torque using a dynamometer, wind the cord around the rim of the spur gear; the dynamometer reading should be in the range of 18.7–31.2 N (1.87–3.12 kgf).
It should be borne in mind that when the shims are removed from under the cup cover when adjusting the bearings, the driven bevel gear shifts towards decreasing the side clearance; therefore, to maintain the clearance under the cup 5 bearings, install additional shims.
Install the cup with the drive bevel gear into the final drive housing.
Tighten the cup mounting bolts to a torque of 60–80 N·m (6–8 kgf·m).
Check the correct engagement of the bevel gears with paint. The length of the imprint must be at least 60% of the length of the tooth (table).
The imprint must be located no closer than 5 mm to the edges of the tooth. In this case, the backlash between the teeth (at the wide part) should be 0.1–0.4 mm.
To change the backlash of bevel gears without distorting the contact, move both gears a distance proportional to the number of teeth of each gear, i.e., move the driven bevel gear 2.2 times (24:11) further than the drive gear.
Install the differential and adjust the differential bearings. Tighten the differential bearing cap bolts to a torque of 250–320 N·m (25–32 kgf·m).
Adjust the differential bearings with nuts 37 (see Fig. 1). After tightening the nuts, the distance between the differential bearing caps should increase by 0.04–0.14 mm.
During adjustment, rotate the differential to install the rollers in the bearings. The crown of the driven spur gear must be positioned symmetrically relative to the crown of the drive gear.
To determine the contact pattern, apply a thin layer of oil paint to the working surfaces of three teeth of the drive bevel gear.
Then, by rotating the drive bevel gear shaft by the splined end in both directions, achieve a clear imprint of the contact pattern on the forward and reverse sides of three to five teeth of the driven bevel gear.
The contact pattern on the tooth of the driven bevel gear should be located closer to the narrow end of the tooth and not reach the edge by 1.5–8 mm (Fig. 3).
In this case, the backlash between the teeth (at the wide part) should be 0.1–0.4 mm. Check the clearance size for at least three teeth of the driven bevel gear, located at equal distances around the circumference.
Methods for correcting the contact pattern and achieving correct gear engagement are given in the table.
According to the recommendations given in the table, correct engagement is achieved by axial movement of the driven and drive bevel gears.
Move the drive bevel gear by changing the thickness of the shim pack. The set of adjusting shims produced by the factory consists of three standard sizes with thicknesses of 0.22; 0.1 and 0.05 mm.
Move the driven bevel gear by changing the thickness of the pack of adjusting shims 4 installed between the flange of the bearing cup 5 and the gearbox housing.
After completing the adjustment, install the bearing caps with sealing gaskets and secure them with bolts.
Using a mandrel, press the flanges onto the splined ends of the drive bevel gear shaft, tighten and cotter pin the flange mounting nuts.
The cotter pin installed in the hole at the rear end of the drive bevel gear shaft must be located in the direction of the straight edge of the flange (i.e., when installing the flange, it must be oriented relative to the shaft hole for the cotter pin).
The orientation of the flange on the shaft is designed to prevent contact between the cotter pin and the yoke of the installed driveshaft.
Due to the improvement of differential gear manufacturing technology, the tooth profile of the side gear and pinion has changed.
The changed gears are not interchangeable with previously produced ones and should only be replaced as a set.
For distinction, marks have been introduced on the side of the small module: on the side gear there is a groove with a diameter of 90 mm, and on the pinion there is a stepped end.
Adjust the bearings of the steering knuckle kingpins during the sixth maintenance TO-2 (after 96,000 km) in the following order:
- - remove the wheels and install stops under the lower covers of the steering knuckles;
- - remove the steering knuckle arms;
- - remove two shims from the shim pack under the arms: one 0.05 mm thick, the other 0.1 mm thick; put 50 g of Litol-24 grease (GOST 21150-87) into the cavity of the arms and install the arms in place; tighten the nuts to a torque of 110–140 N·m (11–14 kgf·m);
- - remove the stops and remove the covers;
- - remove a pack of shims with a thickness of 0.15 mm [(0.05+0.1) mm] from under each cover;
- - install the covers and tighten the nuts to a torque of 110–140 N·m (11–14 kgf·m);
- - install the wheels.
Adjusting wheel hub bearings:
- - jack up the axle on the side of the wheel being adjusted;
- - remove the cover;
- - use a puller to disengage the axle shaft splines from the hub and remove the axle shaft;
- - unscrew the outer nut and remove the lock washer and lock washer;
- - by rotating the wheel by hand, make sure that there is no friction between the brake drum and the shoes;
- - tighten the nut to a torque of 200–250 N·m (20–25 kgf·m); when tightening the nut, rotate the hub to allow the rollers to self-position in the bearings, then loosen the nut by about 1/5–1/6 of a turn. Install the lock washer.
If the pin of the nut does not coincide with the slots of the lock washer, it is allowed to loosen the nut by an amount not exceeding the distance between two adjacent slots.
Install the lock washer, tighten the lock nut to a torque of 400–500 N·m (40–50 kgf·m) and lock it.
To ensure the connection of the wheel inflation hose to the wheel valve, install the axle shaft with the hub cover so that the inflation hose is located in the direction of the wheel valve, symmetrically between the wheel mounting studs.
After completing assembly, check the adjustment of the wheel bearings during a run of 10–20 km.
When adjusted correctly, the hub should be cold or slightly warm. If the hub heats up noticeably to the touch, check the bearing adjustment.
On commercial vehicles, wheel hub bearings 2007124A may be installed, which are not interchangeable with bearings 2007124M.
The wheel hub with the outer rings of bearings 2007124A pressed into it is marked with an annular groove of 220 mm diameter, 2–4 mm wide, at a distance of 38 mm from the end under the hub cover.
Assembling a hub with outer rings of bearings 2007124A and inner rings of bearings 2007124M pressed into it (and vice versa) is unacceptable.
The seal race for bearing 2007124M cannot be used with bearing 2007124A.
The seal race for bearing 2007124A can be used with bearing 2007124M.
The seal race used with bearing 2007124A has an enlarged groove for the cage (diameter 175 mm instead of 172 mm).
Assembling seal races with bearings that do not correspond to them is unacceptable. Wheel hubs with bearings are interchangeable.
