Audi Q7: Repair Information
Shock Absorber Leaks
Vehicles with Coil Springs
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:
Note
Minor oil excretion is advantageous since piston rod oil seal gets lubricated, which increases service life. This applies to shock absorbers on the front and rear axles.
- Oil leakage (shaded in illustration -arrow-) is visible, but dull, matte and possibly dry due to dust.
- One-sided oil or dirt film formation, no dripping.
A shock absorber is not OK under the following circumstances:
- Dripping -arrow-, completely coated with oil film
- A wet oil film that runs down the pipe indicates a leaky shock absorber. A replacement is required in this instance.
Shock Absorbers, Checking when Removed
Vehicles with Coil Springs
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 filled.
A removed shock absorber can be checked by hand as follows:
- Push the shock absorber together by hand.
- Piston rod must move with even resistance throughout entire stroke and without jerking.
- Release piston rods.
- For shock absorbers with sufficient gas pressure, the piston rod returns automatically to its starting position.
Note
- If this is not the case, the shock absorber does not necessarily need to be replaced. As long as oil loss is not large, the effectiveness represents that of a standard shock absorber.
- The damping function is also completely available without gas pressure, as long as there is no large loss of oil. However, this can increase the noise level.
Shock Absorbers, Checking on Shock Tester
Equipment Level with Bolts or Air Suspension
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 printout.
Special tools and workshop equipment required
- Maha Shock Absorber Tester -VAS1990S-, Suspension Strut Test Bed -VAS6636-, or -VAS6640 Suspension Strut Test Bed-
- Suspension Strut Test Bed -VAS6636-
- Suspension Strut Test Bed -VAS6640-
Test Requirements
- Temperature 10 through 40 ºC (50 through 104 ºF).
- Driver in vehicle.
- Tire pressure OK
- Drive vehicle straight onto center of wheel contact plates.
- Front wheels in straight position.
- Mechanical parking brake not engaged, foot brake not pressed.
Threshold
Shock absorber condition can only be judged as follows:
- Sufficient damping effect
or
- 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 specified values are exceeded, the effect of the shock absorber has weakened enough that a replacement is recommended.
Example:
Threshold = 70
- a = greater than 70: insufficient damping effect
- 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 → Chapter "Production Control Number (PR Number) Explanations".
Threshold "a" in mm
Note
- If the readout value is greater than the threshold "a" (table value): insufficient damping effect ⇒ replace shock absorber.
- If the readout value is less than the threshold "a" (table value): sufficient damping effect ⇒ shock absorber does not need to be replaced.
- The level of a vehicle with air suspension is not important for the test.
1) Value not yet determined
Guidelines for Clean Working Conditions
- Thoroughly clean connecting points and their surrounding areas before loosening.
- Place removed parts on a clean surface and cover them so that they do not get dirty. Use foil and paper. Only use lint-free cloths.
- Only install clean parts: remove the replacement parts from their packaging just before installing them.
- Use greases and sealants that are identified by part numbers exclusively.
- Carefully cover or seal opened components if the repair is not performed immediately.
Vehicles with Air Suspension
- Make sure that no dirt enters the pressure air system.
- Clean the area before removing connecting pieces for the air pipe lines or other components of the pressured air system.
- Seal off any open compressed air lines and connections in the pressure system immediately with plugs or cover them.
General Information
Caution
Risk of damaging the threads in the vehicle body.
- The bolts and nuts at all suspension parts must not be loosened or tightened with an impact wrench.
- Always install the bolts and nuts by hand for the first few turns.
- When installing waxed components, contact surfaces must be cleaned. Contact surfaces must be free of wax and grease.
- Welding or adjustment procedures are not permitted on load-bearing or wheel-controlling components.
- Always avoid the following actions with coil springs: Hammer strokes, welding beads, applying color identification later.
- Do not perform any welding or grinding (separating work) near coil springs or suspension struts. Cover coil springs or suspension struts if necessary.
- When loosening or removing and installing hydraulic, pneumatic lines or wires, draw sketches or take pictures. This ensures installation is the same as the original.
- If the cable ties, brackets or mounting elements were removed during the repair procedure, they must be installed at their original location that corresponds to the series production.
- Lightly coat the splines on the outer joint with assembly paste before installing the outer joint into the wheel hub. Refer to the Parts Catalog.
- Never allow the drive axle just to hang loose under the vehicle or to bend them at the joints.
- Vehicles without a drive axle must not be moved, otherwise the wheel bearing will be damaged. If a vehicle must be moved, be sure to note the following:
- Install an outer joint in place of the drive axle.
- Tighten the outer joint to 200 Nm.
- Bonded rubber bushings have a limited range of motion. Only tighten suspension bolts when vehicle is in curb weight position or at standard vehicle height.
- Lifting the wheel bearing in curb weight position (refer to → Chapter "Wheel Bearing in Curb Weight Position, Lifting Vehicles with Coil Spring") or at standard vehicle height (refer to → Chapter "Wheel Bearing at Standard Vehicle Height, Lifting Vehicles with Air Suspension").
- Always replace bonded rubber bushings on both sides of vehicle.
- If the vehicle must still have an axle alignment, only tighten the bolts and nuts that were loosened when making adjustments to the tightening specification. Tighten the bolts and nuts to the specified additional tightening angle after the alignment/adjustment is complete.
WARNING
Risk of accident!
If vehicle will be driving on the streets, all bolts and nuts must be tightened properly!
General Repair Information
A series of significant general notes for individual repair procedures, that would otherwise be given many times at various points throughout the repair manual, is listed here. They apply to this repair manual.
Contact Corrosion
Contact corrosion can occur if incorrect fasteners (bolts, nuts, washers, etc.) are used.
For this reason, only fasteners with a special surface coating are installed.
In addition, rubber or plastic parts and adhesives are made of non-conductive materials.
If there are doubts whether a part should be used again, install a new part according to the Parts Catalog.
Note:
- The use of original replacement parts is recommended, since they are tested and are compatible with aluminum.
- The use of Audi accessories is recommended.
- Contact corrosion damage is not covered under warranty!
Steering Gear
Extreme caution, cleanliness, and properly functioning tools are an essential requirement in performing a faultless and successful steering gear repair. The general safety precautions also always apply when servicing the vehicle.
Seals and Gaskets
- Always replace seals and gaskets.
- After removing seals, inspect contact surface on housings and shafts for burrs and damage and repair if necessary.
- Remove the sealant residue from the fluid seals from sealing surfaces.
Bolts and Nuts
- Loosen and tighten the bolts and nuts from the covers and housings diagonally.
- Do not cant but loosen and tighten especially sensitive parts in diagonal manner in stages, for example servo motor with control module.
- Tightening specifications for non-lubricated bolts and nuts are given.
- Always replace self-locking nuts and bolts.
- Always replace the bolts and nuts, which are tightened with an additional turn.
Electrical Components
Surely everyone has been shocked at one time or another when coming into contact with a metal object. The reason for this is the build-up of static electricity in the human body. This charge can cause malfunctions if it contacts the electrical components of the steering gear.
- Touch a grounded object, such as, a water pipe or a vehicle hoist, before working on electrical components. Do not make direct contact with the connector terminals.
Damaged Threads in Longitudinal Member, Repairing (Subframe to Body)
Procedure for repairing a damaged thread.
Wheel Bearing in Curb Weight Position, Lifting Vehicles with Coil Spring
Special tools and workshop equipment required
- Engine and Gearbox Jack -VAS6931-
- Tensioning Strap -T10038-
- Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-
Note
All chassis component bolts with bonded rubber bushings must be tightened in curb weight position. Refer to → Chapter "Vehicles with Coil Springs, Checking the Curb Weight Position for Axle Alignment".
- Bonded rubber bushings have a limited range of motion. Axle components with bonded rubber bushings must be brought into the position they will be in when driving before they are tightened (curb weight position).
- Otherwise, the bonded rubber bushing will have tension, which will reduce the service life.
- By raising the corresponding suspension using the Engine and Gearbox Jack -VAS6931- and Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-, this position can be simulated on the hoist.
Procedure
- Before starting the procedure, determine the measurement -a-, for example with tape measure, from the center of the wheel to the lower edge of the fender/wheel housing.
Note
The measurement must take place in curb weight position.
- Note the measurement. This will be needed when tightening the bolts/nuts.
Front Axle:
- Engine must be installed.
Rear Axle:
WARNING
Risk of accident!
A vehicle that is not secured can slide off the hoist.
- Before lifting the suspension, the vehicle must secured to the lifting arms on the hoist -arrow B- using the Tensioning Strap -T10038- over the striker pin -arrow A-.
- Place a piece of foam rubber -1- between the side sill and the Tensioning Strap -T10038- and then tension the Tensioning Strap -T10038-.
Note
Be careful not to scratch the side sill.
Continuation for Axles:
- Remove the front wheel. Refer to → Chapter "Wheels and Tires".
- Turn the wheel hub, until the wheel bolt hole is on top.
Caution
Risk of destroying the wheel bearing when installing the wheel bolt.
So that the installed wheel bolt cannot push against the wheel bearing, it (the bolt) must be installed with a washer inserted in between.
- Install the Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149- with a wheel bolt -2- and inserted washer -1- on the wheel hub.
Note
Tightening of the applicable bolts/nuts must only occur if the dimension a that was measured before installation has been attained between the center of the wheel hub and the lower edge of the fender/wheel housing.
- Insert the Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149- in the Engine and Gearbox Jack -VAS6931- and lift the wheel bearing housing until the dimension -a- is reached.
WARNING
Risk of accident!
- Do not lift or lower the vehicle when the Engine and Gearbox Jack -VAS6931- is under the vehicle.
- Do not leave the Engine and Gearbox Jack -VAS6931- under the vehicle any longer than necessary.
- Tighten the applicable bolts and nuts.
- Lower the wheel bearing housing.
- Move the Engine and Gearbox Jack -VAS6931- to the side
- Remove the Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-.
Wheel Bearing at Standard Vehicle Height, Lifting Vehicles with Air Suspension
Special tools and workshop equipment required
- Engine and Gearbox Jack -VAS6931-
- Tensioning Strap -T10038-
- Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-
Note
All chassis component bolts with bonded rubber bushings must be tightened at standard vehicle height. Refer to → Chapter "Standard Vehicle Height for Axle Alignment on Vehicles with Air Suspension, Checking".
- Bonded rubber bushings have a limited range of motion. Axle components with bonded rubber bushings must be brought into the position they will be in when driving before they are tightened (standard vehicle height).
- Otherwise, the bonded rubber bushing will have tension, which will reduce the service life.
- By raising the corresponding suspension using the Engine and Gearbox Jack -VAS6931- and Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-, this position can be simulated on the hoist.
Procedure
- Before starting the procedure, determine the measurement -a-, for example with tape measure, from the center of the wheel to the lower edge of the fender/wheel housing.
Note
- The dimension -a- = the standard vehicle height depends on the suspension installed. Refer to → Chapter "Standard Vehicle Height for Axle Alignment on Vehicles with Air Suspension, Checking".
- The measurement must take place at standard vehicle height.
- Note the measurement. This will be needed when tightening the bolts/nuts.
Front Axle:
- Engine must be installed.
Rear Axle:
WARNING
Risk of accident due to the vehicle sliding off the hoist.
When lifting the vehicle on the hoist the full spring force of the air suspension remains. To bring the wheel bearing into the standard vehicle height the spring force of the air suspension must be completely removed by bleeding the system.
- Before lifting the suspension, the vehicle must secured to the lifting arms on the hoist -arrow B- using the Tensioning Strap -T10038- over the striker pin -arrow A-.
- Place a piece of foam rubber -1- between the side sill and the Tensioning Strap -T10038- and then tension the Tensioning Strap -T10038-.
Note
Be careful not to scratch the side sill.
Continuation for Axles:
- Remove the air suspension system. Refer to → Chapter "Air Suspension System, Filling and Bleeding".
- Remove the front wheel. Refer to → Chapter "Wheels and Tires".
- Turn the wheel hub, until the wheel bolt hole is on top.
Caution
Risk of destroying the wheel bearing when installing the wheel bolt.
So that the installed wheel bolt cannot push against the wheel bearing, it (the bolt) must be installed with a washer inserted in between.
- Install the Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149- with a wheel bolt -2- and inserted washer -1- on the wheel hub.
Note
Tightening of the applicable bolts/nuts must only occur if the dimension a that was measured before installation has been attained between the center of the wheel hub and the lower edge of the fender/wheel housing.
- Insert the Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149- in the Engine and Gearbox Jack -VAS6931- and lift the wheel bearing housing until the dimension -a- is reached.
WARNING
Risk of accident!
- Do not lift or lower the vehicle when the Engine and Gearbox Jack is under the vehicle.
- Do not leave the Engine and Gearbox Jack under the vehicle any longer than necessary.
- Tighten the applicable bolts and nuts.
- Lower the wheel bearing housing.
- Move the Engine and Gearbox Jack -VAS6931- to the side
- Remove the Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-.
Note
- The vehicle may be removed from the vehicle hoist only after the air springs have been filled again.
- Before filling the air spring, check the installation position. Refer to → Fig. "Air Spring Installed Position".
