General, Technical Data (Suspension, Wheels, Steering (coupe)) Audi A5 I

FRONT SHOCK ABSORBERS, VENTING AND EMPTYING

A - Venting through Drill Holes

Secure gas-filled shock absorber vertically in vise, with piston rod facing down.

Scheme 1

Drill a 3 mm hole -arrow A- through the shock absorber outer tube.

Note. Gas escapes when drilling.

Continue drilling until the tube inside is drilled through (approximately 25 mm deep).

Drill a second 6 mm hole -arrow B- through the outer and inner shock absorber tubes.

Hold shock absorber over appropriate container for catching oil and move piston rod repeatedly through entire stroke until no more oil flows out.

B - Open with Pipe Cutter

Special tools and workshop equipment required

1. Pipe cutter, commercially available

Drill a 3 mm hole -arrow- through the shock absorber outer tube or saw through the tube wall.

Scheme 2

Note. Gas escapes when drilling or sawing.

Attach a pipe cutter (commercially available), as shown in the illustration, and cut through the outer shock absorber tube.

Pull the piston rod upward, hold the inner shock absorber tube in place with pliers and push it downward so that it remains in the outer shock absorber tube when the piston rod is slowly raised.

Remove the piston rod from the shock absorber inner tube.

Empty the shock absorber tube.

REAR GAS-FILLED STRUT, VENTING

A - Venting through Drill Holes

Secure gas-filled shock absorber vertically in vise, with piston rod facing down.

Scheme 3

Drill a 3 mm hole -arrow A- through the shock absorber outer tube.

Note. Gas escapes when drilling.

Continue drilling until the tube inside is drilled through (approximately 25 mm deep).

Drill a second 6 mm hole -arrow B- through the outer and inner shock absorber tubes.

Hold shock absorber over appropriate container for catching oil and move piston rod repeatedly through entire stroke until no more oil flows out.

B - Open with Pipe Cutter

Special tools and workshop equipment required

1. Pipe cutter, commercially available

Drill a 3 mm hole -arrow- through the shock absorber outer tube or saw through the tube wall.

Scheme 4

Note. Gas escapes when drilling or sawing.

Attach a pipe cutter (commercially available), as shown in the illustration, and cut through the outer shock absorber tube.

Pull the piston rod upward, hold the inner shock absorber tube in place with pliers and push it downward so that it remains in the outer shock absorber tube when the piston rod is slowly raised.

Remove the piston rod from the shock absorber inner tube.

Empty the shock absorber tube.

POWER STEERING GEAR, EMPTYING

Note. The room temperature must be at least 20° C (68 °F) when emptying the power steering gear.

Hold the power steering gear that will be opened over the oil collecting container and let the hydraulic oil drain.

Clamp the power steering gear horizontally in the vise with the connections facing down.

Place the oil collecting container under the power steering gear.

Move the steering rack over the tie rod approximately 6 times over the from one end to the other.

Dispose of the power steering gear.

SHOCK ABSORBERS, LEAKING

Shock absorbers are frequently rejected and exchanged because of leaks. Examinations on the test stand and on the vehicle have shown that the replacement of a large number of rejected shock absorbers was not justified.

Slight leaking of oil ("sweating") at piston rod seal is no reason to replace a shock absorber. A shock absorber damp with oil is OK under the following circumstances

Scheme 5

1. Oil leakage (shaded in illustration) is visible, but dull, matte and possibly dry due to dust.
2. Oil leakage extends from upper strut connection (piston rod oil seal) no further than lower spring seat -arrow-.

Note. Minor oil excretion is advantageous since piston rod oil seal gets lubricated, which increases service life. This is true for front and rear shock absorbers.

SHOCK ABSORBER NOISES

Shock absorbers are frequently rejected and exchanged because of rumbling noises. Examinations on the test stand and vehicle have shown that there was not complaint with approximately 70 % of the rejected shock absorbers and the replacement was not justified.

With complaints that are interpreted as rumbling or knocking sounds, proceed as follows.

Determine where, when and how the sounds change during a road test on a dry stretch of road with irregularities.

Note. Only in the rarest of cases shock absorbers are the fault for noises.

CHASSIS

Note. The specified values apply to all engine versions. Tracks change with use of wheels with different offset.

Note. The specified values apply to all engine versions. Tracks change with use of wheels with different offset.

Note. The specified values apply to all engine versions. Tracks change with use of wheels with different offset.

Hydraulic Steering Gear

Electromechanical Steering Gear

SHOCK ABSORBERS, CHECKING WHEN REMOVED

Defective shock absorbers are noticeable when driving due to loud rumbling noises - a result of wheel hopping - especially on poor stretches of road. Moreover, they can be recognized by a large loss of oil.

Note. Shock absorbers are maintenance-free, shock absorber oil cannot be topped off.

A removed shock absorber can be checked by hand as follows

Press shock absorber together by hand.

1. Piston rod must move with even resistance throughout entire stroke and without jerking.

Release piston rods.

1. For shock absorbers with sufficient gas pressure, piston rod returns to initial position automatically.

Note. If this is not the case, the shock absorber must be replaced. As long as oil loss is not large, the effectiveness represents that of a conventional shock absorber. The damping function is also completely available without gas pressure, as long as there is no large loss of oil. However, noise may increase.

SHOCK ABSORBERS, CHECKING ON SHOCK TESTER

Shock absorbers can be checked while installed using the shock tester (shock absorber testing device). The damping effect can be evaluated based on the dial reading or print-out.

Special tools and workshop equipment required

1. Boge shock tester or
2. Sachs shock tester V.A.G 1975 or
3. Maha shock absorber tester VAS 1990

Note. Temperature +10 to +40 °C (+50 to +104 °F). Driver in vehicle. Tire pressure OK Drive vehicle straight onto center of wheel contact plates. Front wheels in straight position. Parking not engaged, foot brake not activated.

Threshold

Shock absorber condition can only be judged as follows

1. Sufficient damping effect

or

1. Insufficient damping effect

Note. Intermediate values for reduced damping performance cannot be read out. A prognosis on service life is not permitted. Measured values that occur with the involvement of the suspension travel end stops are incorrect.

The following values apply only to the test stands named above. If the values specified are exceeded, the shock absorber has lost enough of its effectiveness that it should be replaced.

Example

Scheme 6

Threshold = 70

1. a = greater than 70: Insufficient damping effect
2. a = less than 70: Sufficient damping effect

The shock absorber combination installed in the vehicle is indicated by the corresponding PR number on the vehicle data plate.

Production Control Number (PR number) explanation, refer to PRODUCTION CONTROL NUMBER (PR NUMBER) EXPLANATIONS .

Threshold "a" in mm

Note. If the readout value is greater than the limit value "a" (table value) : Damping effect insufficient --> Replace shock absorber. If the readout value is less than the limit value "a" (table value) : Damping effect sufficient --> Shock absorber does not need to be replaced.

Coupe/Cabriolet

See also:
• PRODUCTION CONTROL NUMBER (PR NUMBER) EXPLANATIONS