Details of the front suspension strut and the sequence of their assembly
- 1 - nut with flange;
- 2 - suspension strut bearing;
- 3 - intermediate washer;
- 4 - upper spring plate;
- 5 - spring;
- 6 - shock absorber buffer;
- 7 - protective shell;
- 8 - protective cap;
- 9 - lower lining under the spring;
- 10 - lower spring plate;
- 11 - shock absorber.
Dismantling the suspension strut at the top. After removing both protective caps, you can loosen the nuts «1» And «2» upper rigid suspension strut mount.
Removing the suspension strut at the bottom. The arrow points to the screw connection to the front suspension wishbone at the bottom.
Front dismantled suspension strut
- 1 - the upper bearing of the suspension strut;
- 2 - spring;
- 3 - shock absorber;
- 4 - fork head.
In order to separate the spring from the shock absorber in the dismantled shock absorber, spring clamps are used (arrows).
Left: corner position (A) upper spring plate on the right (R) and left (L) mirror in relation to the screwing axis at the bottom of the forked head (1). The arrow shows the direction of movement (F).
Right: Mounting position of the lower spring plate (1) on shock absorber (2): hole (arrow) located with an outward offset of 90°in relation to the screwing axis (A).
In the front wheel suspension assemblies, much can be disassembled and reassembled on your own, although certain work requires tools from the workshop. Damaged wheel suspension parts must not be straightened or even welded, they only need to be replaced.
Removing the front suspension strut
Removing the suspension strut in the Audi A4 is not particularly difficult. It's also nice that you don't have to re-measure wheel alignment.
1. Obtain new self-locking nuts for attaching the shock strut at the bottom and top, as well as for the upper screw connection of the bearing hinge.
2. Raise both rubber tips in the humidifying reservoir (they cover the upper screw connections of the suspension struts).
3. Unscrew both nuts of an amortization rack under them.
4. Raise and secure the front of the vehicle.
5. Remove the wheel.
6. Disconnect on an amortization rack a wire to the gauge of number of turns ABS.
7. Unscrew the nut of the clamping bolt of the upper axle joint. Remove the clamp bolt.
8. Remove the axle pivots upwards from the wheel bearing housing (steering knuckles). In doing so, never widen the slot in the wheel bearing housing, for example with a screwdriver.
9. Do not depress the tie rod joint.
10. Tilt out the wheel bearing housing.
11. Unscrew the bottom screw connection of an amortization rack.
12. Carefully remove the suspension strut from the wheel arch.
13. Installation: Install the spring strut so that the hole in the lower spring plate faces the center of the vehicle.
14. Tighten the lower shock absorber mount by 90 Nm.
15. Insert the bearing joints into the wheel bearing housing until it stops.
16. Insert the clamping bolt of the upper axle joints, tighten the nut to 40 Nm.
17. Reattach the ABS wire.
18. Tighten the upper nuts of the suspension strut by 20 Nm.
Replacing the front shock absorber
For this work, which is carried out on a dismantled suspension strut, a spring tensioner is required. At least two tensioners are used; three is better. Without using a tensioner, the top flange nut on the damper piston rod piston must not be loosened as the spring is under high preload. Suspension strut parts can fly apart as in an explosion - extreme risk of injury! In addition, a weakened spring cannot be installed.
1. Remove the suspension strut.
2. Clamp the suspension strut by the fork head in a vise. Never tighten in the area of the cylindrical part, otherwise the suspension strut will be crushed.
3. Install the tensioner on the coils of the spring and lightly compress the spring.
4. To prevent the tensioners from slipping, cover the corresponding coils of the spring with duct tape.
5. Loosen the flange nut on top of the suspension strut. Using a wrench with an Allen key, press the shock absorber piston rod in the opposite direction.
6. Remove the spring with accessories.
7. Remove the protective cap and lining under the spring.
8. Separate the spring plate with a plastic hammer and remove it.
9. Installation: put the spring plate on the new shock absorber.
10. Pay attention to the mounting position: the hole in the spring plate must be offset by 90°in relation to the holes in the fork head at the bottom of the shock absorber (tolerance only 2°).
11. Install spring pad, protective cap and sheath, and thrust buffer.
12. Install the spring on the plate, which is still under tension; make sure that the lower end of the coils of the spring adjoins the stop of the spring plate.
13. Put on the top plate of a spring with the bearing of an amortization rack and a washer.
14. Screw the spring plate in accordance with the figure by 11°to the shock absorber screwing axis (below the forked head). There are different directions on the right and left sides.
15. Work precisely: the tolerance is only 2°.
16. Tighten the flange nut at the top on the suspension strut by 60 Nm. Using a wrench with an Allen key, press the shock absorber piston rod in the opposite direction.
17. Loosen the spring tension, making sure that the end of the spring rests against the stop of the spring pad.
Removing the front wheel bearing
Here in numbers (1–3) the fixing bolts of the upper bearing bracket of the front axle are indicated.
The wheel bearing is pressed into the housing with its outer ring, the wheel hub is pressed into the inner ring of the bearing. A new wheel bearing must never be driven into the socket with a hammer, otherwise immediate damage will «mounted with it». Therefore, pressing and pressing the bearing is done by a workshop where a repair press is available.
Replacing the independent axle suspension arm
Both arrows point to the so-called flange nuts, with which the axle pivots are attached to the wheel bearing housing.
Bearing hinges (axle pivots) on the four suspension arms on each outer side of the front axle cannot be purchased separately in the same way as their cuffs. It follows that in the event of a defect in the bearing hinge, it is necessary to immediately change the entire independent suspension arm.
Not so with the rubber mounts on the inside of the axle suspension arms. They can be pressed and pressed individually in the workshop. In this case, it is necessary to strictly adhere to their installation position. We prefer and describe the replacement as a complete assembly, as pressing must be done in a workshop. In addition, in this case, the axle joint is replaced at the same time, thereby eliminating the next defect in the same assembly.
Removing both axle independent suspension arms at the top
1. All self-locking nuts and bolts of the axle suspension arm/bracket must be replaced; get new ones.
2. First, dismantle the bracket at the top: the car must be raised and fixed.
3. Unscrew in an impellent compartment three fixing bolts of an arm.
4. Remove the wheel.
5. Disconnect a wire of the sensor of number of turns ABS on an amortization rack.
6. Unscrew the nut of the clamping bolt of the upper axle joints. Unscrew the clamping bolt.
7. Remove the axle pivots at the top from the wheel bearing housing (steering knuckles). In doing so, never widen the slot of the wheel bearing housing, e.g. with a screwdriver.
8. Do not depress the tie rod joint.
9. Tilt out the wheel bearing housing.
10. Unscrew the bottom screw connection of an amortization rack.
11. Carefully take out from a wheel arch an amortization rack together with an arm.
12. Loosen the screw connections of the axle joints.
13. Mounting: screw on the axle suspension arms, tilting them slightly downwards, so that there is a distance of 55 mm between the outer edge of the bracket and the axle suspension arms (tolerance 2 mm).
14. Tightening torque of the axle suspension arms at the top of the bracket: 50 Nm. Then tighten another 1/4 turn.
15. Reinsert the suspension strut with bracket.
16. Tighten the lower shock absorber mount by 90 Nm.
17. Insert the bearing joints into the wheel bearing housing as far as they will go.
18. Insert the clamping bolt of the upper axle joints, tighten the nuts to 40 Nm.
19. Reattach the ABS wires.
Dismantling (bearing) lower independent suspension arms
1. Replace all self-locking nuts and bolts of the axle suspension arm/axle body bearing support; the same applies to the flange nut on the outside of the axle pivot and the ribbed nuts on the stabilizer link rod.
2. Raise the vehicle and secure it.
3. Remove the wheel.
4. Unscrew the flange nut from the outside on the axle hinge, press the hinge neck out of the conical socket on the wheel bearing housing with an appropriate removable device (e.g. large tie rod puller).
5. Unscrew the bottom screw connection of an amortization rack.
6. Unscrew the ribbed nut of the stabilizer connecting rod, remove the connecting rod.
7. Loosen the screw connection of the axle suspension arm/axle body.
8. Remove the axle support arm.
9. Mounting: Clean the pivot pin. Tighten the axle joint flange nut to 100 Nm.
10. Tighten the lower shock absorber mount to 90 Nm.
11. Insert the screw connection of the axle suspension arm/axle body again. Use the internal holes on the body for this. When tightening, press the axle suspension arm inward. Tighten the nut to 90 Nm. Then tighten it another 1/4 turn.
12. Insert stabilizer link (the arrow indicates the direction of movement), tighten the ribbed nut to 90 Nm.
13. The axle suspension arm/axle body bearing support bolt, its self-locking nut and the large assembly support bolts, as well as the flange nut on the outside of the axle pivot, must be replaced.
Dismantling (guides) lower independent suspension arms
The figure shows the distance «A», by which the upper transverse arms of the independent suspension must be removed from the upper bracket (or their vanishing line), when screw connections are tightened (1).
1. Raise the vehicle and secure it.
2. Remove the wheel.
3. Unscrew the flange nut from the outside on the axle hinge, press the hinge neck out of the conical socket on the wheel bearing housing with a suitable removable device (e.g. large tie rod puller).
4. Loosen the screw connection of the axle suspension arm/axle body.
5. To remove the universal bolt (it cannot be reused), you need to lower the axis body.
6. Therefore, unscrew both the smaller hex bolts on the support plates, as well as the larger bolt (unit support bolt).
7. Remove the axle suspension arm.
8. Mounting: Clean the pivot pin. Tighten the axle joint flange nut to 100 Nm.
9. Insert the screw connection of the axle suspension arm/axle body again. Use the internal holes on the body for this. When tightening, press the axle suspension arm inward. Tighten the nut to 90 Nm. Then tighten it another 1/4 turn.
10. Tighten both smaller hex head bolts on the support plates to 25 Nm, the larger bolt (unit support bolt) tighten to 110 Nm. Then tighten it another 1/4 turn.
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