Before assembling the main gear and differential parts, wash them in washing solution MS 6, MS 8 TU 6-15-978-76, blow with compressed air, check for compliance with their technical requirements
It is recommended to lubricate the parting surfaces and sealing gaskets with UG-6 paste.
When the drive gear is finally installed in the crankcase, it should rotate smoothly, without jamming.
Drain and filler plugs, as well as bolts that enter cavities with oil, must be installed using UG-6 or UN-25 pastes.
The final drive gears are selected in pairs at the factory, and each gear is marked with a set number. If one gear fails, both should be replaced.
Assembling the drive bevel gear shaft
Into cup 10 (see Fig. 1) of the drive bevel gear bearings, press the outer ring of the front bearing 17 until it stops against the shoulder using a mandrel (preference 0009...0059 mm).
Turn the glass and press in the outer ring of the rear bearing 7 of the shaft (preference 010...0.068 mm). Press the inner ring of the rear roller bearing 7 onto the drive gear shaft 15.
Place the spacer sleeve 8 and adjusting washers 9 onto the shaft of the drive gear 15; if no parts have been changed, and before disassembly the gap in the bearings was determined, then the thickness of the package of newly installed washers should be less by the amount of the gap, rounded up up to tenths of a millimeter.
Install front bearing 17.
Install thrust washer 11, process flange 13 (without dirt deflector) onto the shaft splines and press it in.
Put on the nut washer and secure the flange with nut 14 (lock the nut only after checking the preload of the bearings).
The differential cups must have the same serial number of the kit and marks that should be aligned during assembly.
Gears and differential cups should be lubricated with engine oil during assembly.
Install the right differential cup on the plate, place the bearing on the chamfer of the cup neck and press it in using a mandrel (bearing tension - 0.020-0.055 mm).
The sequence of operations for assembling the left differential cup is the same as for the right one.
Install the left differential cup on a stand with a hole in which the journal and bearing should be placed. Install the support washer and left axle gear into the cup.
Insert the satellite pin to a depth of about 5 mm into the hole in the differential cup, orienting the axis of the hole in the pin parallel to the axis of the hole for the pin in the differential cup, and press it in with light blows of a hammer until the pin appears from the hole by about 5 mm.
Place the support washer and satellite on the finger and, holding them with your hand, press the finger until the holes for the pin coincide.
Press in the pin with a special mandrel to a depth of 17.05-18.05 mm. Place the body of the cross and the opposite satellite with the support washer into the cup on the finger.
Press in the second finger as described above, and then the remaining two.
Place the right axle shaft gear with the support washer on the satellites, install the right differential cup, aligning the cups according to the marks made with a core during disassembly, and tighten the bolts by hand, installing locking plates on them in pairs.
Remove the differential from the stand and install it in a vice. Tighten the bolts evenly.
The tightening torque of the bolts is 100-120 Nm. Bend the locking plates onto the edge of each bolt.
Install the driven gear onto the differential and secure it with bolts and locking plates. Bolt tightening torque: 160-200 Nm.
The engagement of the differential gears and their rotation in the assembled differential must be free when turned by hand.
Permissible runout of the driven gear torus during installation. on the bearing journals of the assembled differential should not exceed 0.12 mm.
Assembling the main transmission
Install the drive bevel gear housing, complete with bearings and shims, into the rear axle housing.
The set of adjusting shims produced by the plant consists of five standard sizes with a thickness of 1.0; 0.5; 0.2; 0.1 and 0.05 mm.
During assembly, the gearing of the bevel gear teeth and the differential bearings are adjusted at the same time.
The number of gaskets is selected experimentally, focusing on the shape of the contact patch in engagement. Initially, the previously installed kit is installed.
Under the flange of the glass, gaskets with a thickness of 0.05 mm - at least two pieces and 0.1 mm - at least one piece must be installed, and the rest - as necessary, and thin gaskets must be installed on both sides of the set of gaskets.
Steel adjusting shims must be lubricated with spindle oil AU or industrial I-30 before installation.
The bolts securing the bearing cup of the drive gear must be finally tightened with a torque of 70-100 Nm, while the drive gear must rotate smoothly, without jamming.
Install the differential into the crankcase onto the bearing housings.
Tighten the adjusting nuts by hand and install the bearing caps.
To avoid damage to the threads on the crankcase, covers and nuts, when installing covers, ensure that the threads on the mating parts match.
The bearing cap bolts must be tightened with a torque of 160-200 Nm.
The gap is measured with an indicator installed on the wide part of the tooth (Fig. 2).
Adjust the tension of the differential bearings and the engagement of the gears along the contact patch, as described in the article - “Adjusting the main gear.”
Installation of brakes and wheel hubs on the rear axle.
The outer rings of the bearings are not interchangeable, therefore, if necessary, each bearing is replaced as a set.
Install the wheel hub and adjust the clearance in the wheel bearings.
Adjustment is carried out as follows:
- 1. Tighten the adjusting nut to a torque of 60..80 Nm, while turning the hub in both directions to ensure correct installation of the rollers in the bearings. Axial play is not allowed, the hub should not rotate after tightening;
- 2. Unscrew the adjusting nut approximately 45°. Install the lock washer.
If the hole in the lock washer does not coincide with the pin on the adjusting nut, you can try turning the washer 180°; a slight turn of the nut in any direction is also allowed;
- 3. Tighten the locknut to a torque of 250-300 Nm. In operation, when checking the axial gap with an indicator head, the gap should be within 0.125-0.25 mm.
The correctness of the adjustment is checked by heating the hubs after a run of 8-10 km. Slight heating of the hubs is allowed only for new bearings.
In case of significant heating, the adjustment should be repeated. When checking, do not use the brakes, because they can cause significant heating.
The axle is marked at the factory by impact on the rear of the right axle housing housing and contains information about the final drive ratio, the date of manufacture and the catalog number of the axle assembly.
Installing axle shafts
Install the cuff body along with the cuff and axle shaft gasket onto the axle studs. Insert the axle shafts with the splined end into the differential side gears.
Place the axle flanges onto the wheel hub studs. Place expansion bushings and spring washers on the studs, screw in the nuts and tighten them to a torque of 70-90 Nm.
The rear axle is installed on the bus in the reverse order of disassembly.
Drive axle test
The assembled rear axle must be checked on a stand or by driving the car. The tested bridges must meet the following requirements (at the end of the tests):
- 1. Pronounced noise of the main gear gears, as well as knocking and sharp noise in the differential with one braked drum, are not allowed;
- 2. The installation locations of the drive gear and differential bearings in the crankcase and crankcase cover, as well as the installation locations of the wheel hub bearings, must be cold or warm, but not more than 50°C; heating of the brake drum is also allowed no more than 50°C (check can be done by hand by touch);
- 3. There should be no oil leakage through the cuffs and in the connections.