The design of the central gearbox of the front axle is shown in fig. 1, wheel gears and pivot device in fig. 2, 3, the hinge of equal angular velocities in fig. 4

Caring for the front drive axle consists in maintaining the required oil level and replacing it in a timely manner; checking seals and tightening threaded connections.

Central gearbox and wheel brake actuator

MAZ wheel drive and pivot

Constant velocity joint bearings are lubricated regularly according to the lubrication chart, and more often when operating in very dusty and polluted conditions.

To lubricate the hinge bearings, turn the wheel, or to the left until it stops, unscrew all plugs 10 (Fig. 4) and, screwing the grease fitting in sequence, fill the cavity of the cross 6 with grease until it appears in the opposite hole.

Wheel Drive (with CNS) and Pivot

Periodically check the tightness of the bolts securing the cover and supports to the axle housing, the nuts securing the drive gear housing to the axle beam, the nuts securing the king pin bearing caps and the steering knuckle lever, the bolts securing the carrier to the wheel hub.

Constant Velocity Joint

Adjustment of bearings 28, 29 (fig. 1) of the drive bevel gear 32 is similar to the adjustment in the central gearbox of the rear axle.

Adjusting the engagement of the bevel gears is similar to the middle axle.

The difference is that the bearings of the 3rd differential and the gear engagement are adjusted directly on the axle without disassembly.

In this case, the tightness of the differential tapered bearings is made by adjusting nuts 2 through the holes in the axle beam with the stopper 1 removed.

Lubrication of bearings 17, 19, 8 kingpins (Fig. 2, 3) is carried out through oilers installed on each kingpin: from above on the cover and lever, from below - behind the steering knuckle.

The pivot bearings are adjusted on the suspended bridge with bolt 10, ensuring a gap of 0.1 - 0.2 mm between the end of the bolt and the pivot by turning the bolt all the way and then unscrewing it by 1/10 - ⅛ of a turn.

Front axle repair

Repair of the front steerable drive axle (FDA) consists in replacing worn or damaged parts after disassembling the assembly and removing the damage to the parts.

Central gearbox and wheel brake actuator

MAZ wheel drive and pivot

Wheel Drive (with CNS) and Pivot

  • 1. After removing the bridge from the vehicle, disassemble it in the following sequence (Fig. 1, 2, 3.):
  • 1.1. Drain the oil from the crankcase of the central gearbox and wheel gears, having previously unscrewed all the plugs in the crankcase, hubs and wheel gear covers.
  • 1.2. Disconnect the transverse link 23 (fig. 1) from the trapezoid levers by unscrewing the fastening nuts, after removing the cotter pins.
  • 1.3. Remove covers 40 (fig. 2, 3) of wheel gears with gaskets by unscrewing nuts 34 studs and spin washers.
  • 1.4. Remove the carrier 33 of the wheel gears by unscrewing the bolts 42 and removing the washers. Remove rubber seal 32.
  • 1.5. Remove the drive gears 37 of the wheel gears, after removing the retaining rings 36 from the knuckles of the hinges 15. Inspect the parts and replace if damaged.
  • 1.6. Remove the hubs of 2 gears with driven gears, for which:
  • - bend the antenna of the washer Z0, unscrew and shine the lock nut 31, remove the washer with the pin 29 and unscrew the nut 28;
  • - remove the gear hub from the driven gear of the wheel drive, remove the circlip 1 and remove the hub from the gear.

Possible malfunctions of drive axles and methods for their elimination


- Reason


Increased bridge heating

- And too much or too little oil in the gearbox and wheel drive housing

Check and top up oil level in crankcases

- The adjustment of the engagement of the main gear bevel gears is broken

Adjust gear mesh

- The adjustment of the conical bearings of the gearbox and hubs is broken

Adjust bearings

Increased bridge noise

- The adjustment of the engagement of the main gear bevel gears is broken

Adjust gear mesh

- Deterioration of the conical bearings of the drive gear of the main gear and the cross-axle differential or violation of their adjustment

Check the condition of the bearings, if necessary, replace and adjust their tightening

- Large gear wear

Replace worn gears

Increased bridge noise at the turn

- Increased wear of gears, pinion bushings and differential bearing washers

Disassemble differential and replace worn parts

Noise in wheel gear

- Wear of wheel gears and satellite bearings

Replace worn parts

- Insufficient oil level

Add oil to the wheel housing

Oil leaking through seals

- Worn or damaged cuffs

Replace cuffs

1.7. Removing and disassembling the wheel hub:

  • - fix the puller on the hub, remove the hub assembly with the trunnions, after mooring or supporting it.

External inspection to determine the presence of defects and, if necessary, disassemble to replace parts in the following order:

  • - install the hub with the drum up and remove the cover with the cuff, checking for lubrication in the area of ​​​​the cuff of the cover, removing the cover with cuffs and the gasket, as well as the inner bearing rings;
  • — unscrew the air duct 3 from the adapter, and the adapter from the air supply head housing (with CNSh);
  • - take out the air supply head by removing the inner ring of the bearing and remove the sealing rings (from the TsNSh);
  • —if parts are damaged, replace them.
  • 1.8. Remove the pads 4, 26, having first removed the spring 18 (Fig. 1), bolts, remove the washers and plates of the axles of the pads and remove the sealing rings.
  • 1.9. Before removing the expander cams 15, unscrew the bolts 11 fastening the washers of the adjusting levers (left, right) and remove the spring and thrust washers.

Before removing the fists, first remove the shims 14, the support bushing 17 and the sealing ring 16.

  • 1.10. Remove bushing 23 from pin 25 (Fig. 2, 3) and remove rubber sealing ring.
  • 1.11. Removal and disassembly of the trunnion:
  • - unscrew the bolts 20 fastening the trunnion to the knuckle 7, remove the washers, oil catcher with gasket;
  • - remove the trunnion 25 left (right) and the sealing rings 6 holes for the TsNSh and venting (holes for the TsNSh - axial symmetry of the flange and groove milling). If necessary, remove the cuff 22 with a puller, remove the thrust ring 21.

By external inspection and measurement, determine the condition of the collar, ring and bearing in the trunnion and the surface of the trunnion.

When replacing a bearing with a puller, remove it from the pin.

1.12. Remove the hinges after removing the pins, supporting the inner fist to prevent damage to the cuff and bearing in the support.

By external inspection, determine the state of operation of the surfaces of the hinge knuckles for the cuff and bearing.

In case of significant wear of the working surfaces, replace the hinges.

1.13. Disassembly of the central gearbox and removal of the crankcase cover with differential.

Before removing the drive gear 32 (Fig. 1), it is necessary to remove the knuckles 7 (Fig. 2, 3) and supports 12 in the following sequence:

  • - unscrew the nuts 9 of the studs securing the lever 11, the top cover, the bottom cover and the fastening bolts;
  • - remove the levers 22 (Fig. 2) of the steering linkage, unscrew the bolts securing the lever to the steering knuckle, having previously unpinned them and removed the bottom cover 18 (Fig. 2, 3) with gaskets;
  • —remove the thrust washer (when installing a thrust roller bearing instead of a ball bearing), thrust bearing with spacer washer 16 and rings after removing bearing 17;
  • - remove the rotary knuckle 7 from the upper kingpin of the support 12. to remove the supports, it is necessary to unscrew the bolts 14 that fasten the supports to the crankcase flanges 6 (Fig. 1) and cover 8 and shock absorber brackets without washers, remove the sealing ring;
  • - check the condition of the oil seal and needle bearing. If replacement is necessary, remove the cuff and bearing with a puller by removing the retaining ring.

To remove the drive gear, it is necessary to unscrew the bolts securing the drive gear housing 32 to the axle housing, removing the washers.

After removing the drive gear, remove the shims 31 (sealing - if any).

Removing cover 8 produces after unscrewing the bolts 9 fastening the cover to the axle housing without washers, after removing the gasket.

Remove differential 5 with pinion 7 from axle housing 6.

Remove the drive gear, cover and differential when the axle beam is in a vertical position (cover at the top).

External inspection to determine the technical condition of the cover and crankcase of the bridge, if defects are found, replace the parts.

  • 1.14. Dismantling, control and adjustment of the drive gear, differential, central and wheel gears should be carried out by analogy with the rear axle.
  • 1.15. Assemble the front drive axle in the reverse order of disassembly. All friction parts must be lubricated with gear oil, cuffs with Litol-24 type grease.
  • 1.16. To install the hub with the CNS on the trunnion, after installing the protective cover on the trunnion to protect the cuffs of the head from damage.