Specifications & Procedures Audi A8 D3

IDENTIFYING SUSPENSION VARIATIONS

Various suspensions are offered as options. These variations are identified by part numbers. Running gear version installed in vehicle is indicated by the factory weight code on the vehicle data plate. (Scheme 1) Vehicle data plate is located in spare tire well and in service book. The following table identifies suspension versions. Identifying proper suspension version is critical for wheel alignment. See IDENTIFYING SUSPENSION VARIATIONS table.

IDENTIFYING SUSPENSION VARIATIONS

Scheme 1

FRAME & UNDERBODY

The vehicle may only be lifted at the points shown in order to prevent damaging the floor of the vehicle and to prevent the vehicle from tipping. (Scheme 2) The vehicle should NEVER be lifted by the engine oil pan, the transmission, or the front or rear subframe. Otherwise major damage may be caused.

Scheme 2

WHEEL ALIGNMENT PROCEDURES

Note. While limited information is available, vehicle manufacturer does not support alignment information using aftermarket alignment equipment. To properly align vehicle, it is recommended to use VAG 1813 alignment computer. All procedures in this article are written using VAG 1813 alignment computer.

PRELIMINARY CHECKS

Before beginning wheel alignment procedures, ensure following items are checked

1. Ensure alignment equipment is properly calibrated.
2. All wheels and tires are of approved size (all 4 identical) and tires are properly inflated. Tread depth has no more than .08" (2 mm) difference between tires on same axle. Correct as necessary.
3. Check suspension components for looseness or damage. Correct as necessary.
4. Check wheel bearing play and condition. Correct as necessary.
5. Check steering components for looseness or damage. Correct as necessary.
6. Compensate for wheel runout. Permissible lateral runout of the wheel rims may already exceed the specified toe setting tolerance. In this case, a correct toe adjustment is not possible without compensating for wheel runout.
7. Fuel tank full. Spare tire and tools stored in appropriate storage area. Windshield washer reservoir full. Correct as necessary.
8. On vehicle equipped with level control, turn ignition on and allow height control process to run until completed.

Vehicles That Have Been In Accidents

On vehicles which have been in accidents, BEFORE checking or adjusting toe or toe constant "S", steering rack must be in midway position. Place steering rack in midway position as instructed by wheel alignment computer. On steering gear, remove sealing bolt and install Centering Bolt (VAG1907). (Scheme 3) See SPECIAL TOOLS.

It may be necessary to have an assistant move steering wheel until centering hole in rack is felt. With rack locked in place, check whether steering wheel is mounted as horizontal as possible on steering column when wheels are in straight-ahead position. Reposition steering wheel, if necessary. Otherwise, centering of toothed shaft cannot be guaranteed. See appropriate AIR BAG RESTRAINT SYSTEM article in RESTRAINTS.

After toe-in is set, remove centering pin. Reinstall sealing bolt, and torque to 16 ft. lbs. (22 N.m).

Note. If steering wheel position was changed, and vehicle is equipped with Electronic Stability Program (ESP), zeroing of steering angle sensor must be performed using VW factory scan tool. For zero position of steering angle sensor procedure, see appropriate ANTI-LOCK article in BRAKES.

Scheme 3

WHEEL ALIGNMENT WORK SEQUENCE

Perform wheel alignment is the following sequence

1. Check and adjust rear axle camber.
2. Check and adjust rear axle toe.
3. Check and adjust front axle camber.
4. Check and adjust toe-in curve on front axle.
5. Check and adjust front axle toe at starting position.

Note. If steering wheel position was changed, and vehicle is equipped with Electronic Stability Program (ESP), zeroing of steering angle sensor must be performed using VW factory scan tool. For zero position of steering angle sensor procedure, see appropriate ANTI-LOCK article in BRAKES.

CASTER ADJUSTMENT (FRONT OR REAR)

Before attempting any adjustments, see PRELIMINARY CHECKS and WHEEL ALIGNMENT WORK SEQUENCE . Front and rear caster are not adjustable. If caster is not as specified, locate and replace damaged or worn suspension parts.

CAMBER ADJUSTMENT (REAR)

Before attempting any adjustments, see PRELIMINARY CHECKS and WHEEL ALIGNMENT WORK SEQUENCE. Loosen eccentric retaining nut (A) located on the lower rear control arm. (Scheme 4) Set camber by turning eccentric bolt (B) until specified camber value is met. See WHEEL ALIGNMENT SPECIFICATIONS. Tighten eccentric nut. Recheck rear camber after adjustment.

Note. Maximum adjustment range is 90 degrees to the left or right of the center position.

Scheme 4

Rear Toe Adjustment

Before attempting toe adjustment, see PRELIMINARY CHECKS and WHEEL ALIGNMENT WORK SEQUENCE. Loosen toe eccentric securing nut (C). Adjust toe by turning eccentric bolt (D) to specified value. See WHEEL ALIGNMENT SPECIFICATIONS. (Scheme 5) Tighten nut, and recheck alignment angles after adjustments.

Scheme 5

CAMBER ADJUSTMENT (FRONT)

Note. Front camber cannot be adjusted. Camber can be centered evenly by moving the subframe within specified tolerances.

Before attempting any adjustments, see PRELIMINARY CHECKS and WHEEL ALIGNMENT WORK SEQUENCE .

Front wheel camber cannot be set separately. Camber can be evened out uniformly, by loosening subframe bolts and shifting subframe position until correct camber range is obtained.

Working under vehicle, remove sound-deadening pan. Loosen subframe bolts No. 1 and 2 on both left and right sides. (Scheme 6) While observing wheel alignment computer, use a plastic coated pry bar to press subframe from side to side until specified value is reached. (Scheme 7) See WHEEL ALIGNMENT SPECIFICATIONS. Using NEW bolts and washers, torque subframe bolts to 111 ft. lbs. (150 N.m), plus an additional 90°. After subframe bolts are torqued, recheck camber and toe-in range and readjust as necessary.

Scheme 6

Scheme 7

TOE-IN CURVE CHECK & ADJUSTMENT

Note. An incorrectly adjusted toe-in curve adjustment causes the vehicle to pull to one side when braking or accelerating or when driving over bumps. Toe-in curve adjustment can also be referred to as toe constant "S" adjustment.

If the suspension is compressed or extended its toe will change depending on the amount of compression or extension. The resulting toe measurements are described as the toe in curve. The change in the toe constants "S" is adjusted when the vehicle is raised by vertically shifting the toe head. (Scheme 11)

The wheel alignment computer calculates the toe constant "S" through a measured value in the starting position and through a measured value in lifted position. It compares the actual values with the specified values and displays them on the screen. Depending on suspension different adapters are required for lifting.

Toe-in curve is adjusted when vehicle is raised to initial setting position, by vertical adjustment of the tie-rod end. Different adapters are needed for lifting, depending on suspension variation. To identify application of suspension and adapter (Scheme 8) To identify adapter, see SPECIAL TOOLS.

To prepare vehicle for checking toe-in curve adjustment, place vehicle in initial position. See BRINGING VEHICLE INTO INITIAL POSITION FOR TOE IN CURVE ALIGNMENT (SUSPENSION VARIATIONS 1BA, 1BM, 1BE, 1BD, 1BG, 1BN & 1BT) or BRINGING VEHICLE INTO INITIAL POSITION FOR TOE-IN CURVE ALIGNMENT (SPORT SUSPENSION 1BE) .

Scheme 8

Bringing Vehicle Into Initial Position For Toe In Curve Alignment (Suspension Variations 1BA, 1BM, 1BE, 1BD, 1BG, 1BN & 1BT)

Due to the different alignment platforms, it may be necessary to raise vehicle at front axle so that it is possible to insert VAG1925 spacer. After vehicle is lowered, it should be bounced to resettle suspension. To place vehicle in initial position for alignment perform the following

1. Install Spacer Gauge (VAG1925/5) with the Adapters (VAG1925/2). See «SPECIAL TOOLS»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures).
2. Unscrew both thread spindles until they just come to rest against front bolts of subframe carrier. (Scheme 6) This MUST NOT raise vehicle. Vehicle must be standing on its wheels. Vehicle is now in initial position. On vehicles with a level control system, turn ignition on and wait until vehicle height has settled.
3. At this point, alignment program checks whether actual toe setting per wheel corresponds to specified value of +10' +/- 30' (rough presetting). If toe is not as specified, adjust toe-in to specification. See «TOE ADJUSTMENT (FRONT)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__toe-adjustment-front).
4. Place lifting jacks under front end jacking points and lift vehicle 2.4" (60 mm). With vehicle lifted as specified, push cylinder from threaded spindles and fix with safety bolts. (Scheme 9) Ensure that safety bolts are correctly positioned. Lower vehicle onto distance caliper.
5. Observe and compare toe-in constant "S" measurement on alignment computer to specifications. See «WHEEL ALIGNMENT SPECIFICATIONS»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__wheel-alignment-specifications). If toe-in constant "S" measurement is as specified, check toe-in. See «TOE ADJUSTMENT (FRONT)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__toe-adjustment-front). If toe-in constant "S" measurement is not as specified, adjust as necessary. See «ADJUSTING TOE-IN CURVE (ALL MODELS)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__adjusting-toe-in-curve-all-models).

Scheme 9

Scheme 10

1. Place lifting jacks under front end jacking points and lift vehicle. Install Adapters (VAG1925/2 and VAG1925/5). See «SPECIAL TOOLS»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures). (Scheme 10)
2. Lower vehicle onto adapters. Vehicle is now in initial position.
3. At this point, alignment program checks whether actual toe setting per wheel corresponds to specified value of +10' +/- 30' (rough presetting). If toe is not as specified, adjust toe-in to specification. See «TOE ADJUSTMENT (FRONT)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__toe-adjustment-front).
4. Place lifting jacks under front end jacking points and lift vehicle. With vehicle lifted as specified, push cylinder from threaded spindles. Ensure that locking pins are correctly positioned. (Scheme 9) Lower vehicle onto spacer gauge. Observe and compare toe-in constant "S" measurement on alignment computer to specifications. See «WHEEL ALIGNMENT SPECIFICATIONS»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__wheel-alignment-specifications).
5. If toe-in constant "S" measurement is as specified, check toe-in. See «TOE ADJUSTMENT (FRONT)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__toe-adjustment-front). If toe-in constant "S" measurement is not as specified, adjust as necessary. See «ADJUSTING TOE-IN CURVE (ALL MODELS)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__adjusting-toe-in-curve-all-models).

Adjusting Toe-In Curve (All Models)

1. Before attempting toe-in curve adjustment, see «BRINGING VEHICLE INTO INITIAL POSITION FOR TOE IN CURVE ALIGNMENT (SUSPENSION VARIATIONS 1BA, 1BM, 1BE, 1BD, 1BG, 1BN & 1BT)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__bringing-vehicle-into-initial-position-for) or «BRINGING VEHICLE INTO INITIAL POSITION FOR TOE-IN CURVE ALIGNMENT (SPORT SUSPENSION 1BE)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures).
2. On tie rod end, loosen nut "A". (Scheme 11)
3. Unscrew bolt "B" about.160" (4 mm). Press down on tie rod end until it stops.
4. Screw in adjustment bolt "B" until toe-in curve specified value is reached. See «WHEEL ALIGNMENT SPECIFICATIONS»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__wheel-alignment-specifications).
5. Tighten nut "A" to 37 ft. lbs. (50 N.m). Recheck toe-in curve.
6. Tighten bolt "B" to 62 INCH lbs. (7 N.m).
7. Lower vehicle to initial position. Screw threaded spindle down. For vehicles with standard suspension only, bounce vehicle several times and allow suspension to settle. This is not necessary on vehicles with sport suspension.
8. Wheel alignment computer will check toe constant "S" value again. If values are as specified, set toe-in. See «TOE ADJUSTMENT (FRONT)»(/audi/a8/d3-2002-2005/remont/wheel-alignment/#specifications-procedures__toe-adjustment-front). If values are not as specified, repeat toe-in curve adjustment procedure.

Scheme 11

Scheme 12

TOE ADJUSTMENT (FRONT)

Before attempting toe adjustment, see PRELIMINARY CHECKS and WHEEL ALIGNMENT WORK SEQUENCE. Loosen lock nut "B" on tie rod. (Scheme 13) Also, loosen rack boot outer clamp. Adjust toe by turning hex nut "A" until proper setting is reached. Do not allow boot to twist during adjustment, straighten twisted boots when toe in is set. Tighten tie rod lock nuts and clamps. Recheck toe adjustment.

Scheme 13

Note. If steering wheel position was changed, and vehicle is equipped with Electronic Stability Program (ESP), zeroing of steering angle sensor must be performed using VW factory scan tool. For zero position of steering angle sensor procedure, see appropriate ANTI-LOCK article in BRAKES.

Scheme 14

WHEEL ALIGNMENT SPECIFICATIONS

WHEEL ALIGNMENT SPECIFICATIONS - FRONT (A8 & S8: VEHICLES UP TO AUGUST. 1999; VIN 4D_X_004999)

Note. Vehicles manufactured from September, 1999 may identified by braces on the front subframe. (Scheme 15)

Scheme 15

WHEEL ALIGNMENT SPECIFICATIONS - FRONT (A8 & S8: VEHICLES FROM SEPT. 1999; FROM VIN 4D_X_005001)

REAR AXLE WHEEL ALIGNMENT SPECIFICATIONS (A8 & S8 - ALL VARIATIONS)

ADDITIONAL VEHICLE DATA

The additional vehicle data is intended to speed up and permit more accurate diagnosis in the event of minor accident. A slight deviation from the data, with no obvious detriment to performance does not automatically represent a problem. For production reasons, this data may sometimes be outside the tolerances stated even in the case of a new vehicle.

Scheme 16

Scheme 17

Scheme 18

See also:
• IDENTIFYING SUSPENSION VARIATIONS
• PRELIMINARY CHECKS
• WHEEL ALIGNMENT WORK SEQUENCE
• WHEEL ALIGNMENT SPECIFICATIONS
• BRINGING VEHICLE INTO INITIAL POSITION FOR TOE IN CURVE ALIGNMENT (SUSPENSION VARIATIONS 1BA, 1BM, 1BE, 1BD, 1BG, 1BN & 1BT)
• TOE ADJUSTMENT (FRONT)
• ADJUSTING TOE-IN CURVE (ALL MODELS)
• TOE-IN CURVE CHECK & ADJUSTMENT