The design of the wheel part and the steering knuckle assembly of the front drive axle is shown in Fig. 1.
Disassemble the steering knuckle assembly only when replacing the lubricant in the steering knuckle housing, when adjusting the kingpin bearings, and in the event of a malfunction (breakage of constant velocity joint parts, destruction of the kingpin bearing).
When disassembling the assembly, the worn-in parts of the joint must not be mismatched. In addition, it is important to maintain the relative position of the joint parts.
Disassembling the steering knuckle assembly
Close the wheel valves, remove the protective cover and disconnect the air supply hose 2 from the wheel valve of the wheel being removed.
Loosen the wheel nuts.
Raise the front of the vehicle and place a stand under the front end of the frame.
Unscrew the wheel nuts and remove the wheel.
Disconnect the hose of the brake system, sealing system and tire inflation system.
Remove the split pin and unscrew the nut securing the ball pin of the steering linkage rod, the pitman arm rod or the power steering end piece (if the right steering knuckle assembly is being disassembled).
Use a puller to press out the ball pins.
Unscrew the bolts securing the hub cover, unscrew the air supply elbow from the axle shaft 6 and remove the hub cover together with the seal and the air supply hose.
Use a puller to remove axle shaft 6.
After bending the edge of the lock washer, unscrew the lock nut 7, remove the lock washer and the locking washer.
Unscrew nut 10 and remove the wheel hub assembly with the brake drum.
Use a pry bar to remove the brake shoe tension spring.
Unscrew the nuts securing the brake shield and the steering axle 4.
Remove the brake shield assembly with the brake shoes, wheel cylinder 11, cage, dust seal and washer.
Remove the steering axle from the studs of the steering knuckle housing.
Remove the parts of the constant velocity joint (Fig. 2).
Use paint to mark the relative positions of the worn-in parts of the joint.
Remove the lubricant from the steering knuckle housing and the ball joint cavity.
Unscrew the bolts securing the oil seal 10 (Fig. 3) of the ball joint and remove the oil seal.
Remove the rubber plug 16 from the groove of the steering knuckle housing.
Unscrew the nut securing the arm 7 and, lightly tapping the arm with a hammer, remove the expansion cone bushings 3 and the arm with the shim pack 2 from the studs.
Unscrew the nuts securing the cover 18 and remove the cover together with the pack of adjusting shims 17.
Secure the shim packs to the arm 7 and the cover 18.
Press out the outer rings of bearings 9 and 19; using a puller, remove the inner rings of the bearings assembled with the rollers. Remove the steering knuckle housing.
If it is necessary to replace the oil seal 10, unscrew the nuts securing the ball joint 15 and use a pry bar to remove it, using the recesses of the ball joint flange.
Assemble the steering knuckle assembly in the reverse order of disassembly.
Before installing the constant velocity joint and the kingpin bearings, be sure to lubricate the mating surfaces of the parts.
The sealing gaskets of the ball joint, the oil seal and the steering axle, the mating surfaces of the steering knuckle housing 1, the arm 7 and the cover 18 must be lubricated with a thin layer of sealing lubricant; the neck of the ball joint under the axle housing is to be lubricated with graphite lubricant.
Before installing the inspection hole plug or the studs of the steering knuckle housing, also apply sealing lubricant to the threaded surface of the holes.
Before installing and securing the ball joint sealing parts (oil seal cage, collar, sealing and spacer rings, oil seal cover), adjust the preload of the kingpin bearings.
Adjust the bearings by changing the thickness of the adjusting shim packs 2 and 17.
The set of adjusting shims produced by the factory consists of four standard sizes with thicknesses of 0.5, 0.22, 0.1 and 0.05 mm.
Each pack of adjusting shims installed under the arm 7 and the cover 18 must contain at least two shims 0.05 mm thick, located on both sides of the pack.
The amount of torque required for smooth rotation of the steering knuckle housing should be 2.2–2.7 kgf·m, which corresponds to a force of 8–10 kgf applied to the end of the steering linkage arm (cast integrally with the knuckle housing).
The force required for smooth rotation of the knuckle is determined using a dynamometer (Fig. 4).
If the force value is outside the specified limits, select adjusting shims 2 and 17 (see Fig. 3) to achieve the required turning force.
After adjustment, the thickness of the adjusting shim packs under the arm and the cover should not differ by more than 0.05 mm.
When installing the ball joint oil seal, make sure that the spring does not fall out of the seal groove.
After installing the oil seal cover, the recesses under the surface of the ball joint should be located along an axis perpendicular to the axis of the kingpins.
When assembling, install the constant velocity joint parts in accordance with the marks made during disassembly.
Before installation, impregnate the dust seal with transmission lubricant.
After installing the hub assembly with the brake drum, adjust the hub bearings.
If necessary, adjust the clearance between the brake shoe linings and the drum.
After assembly, fill the steering knuckle housing with lubricant through the filler hole (which is also the inspection hole).