Rear Knuckle: Service and Repair
Removing and installing wheel bearing housing (wheel carrier)
Removal
1. Raise vehicle and remove wheel.
2. Loosen and unscrew axle nut (wheel-side drive shaft fastening).
3. Open the plug connection on the wheel carrier and pull out the plug for the brake pad wear indicator and the speed sensor. Loosen plug housing on the wheel carrier.
4. Remove the brake caliper from the wheel carrier and suspend it in the wheel arch (do not open brake hydraulics).
5. Disengage the parking brake cable from the parking brake lever in the vehicle interior. Disengaging the parking brake cable includes:
- Opening the oddments tray on the center console, removing insert and base
- Disengaging tab washer of the turnbuckle from the retaining lug on the upper and lower sides.
- Disengaging the relevant parking brake cable from the turnbuckle.
Information
^ When replacing the wheel bearing, the wheel carrier or the wheel hub, the parking brake cable can remain fitted. In that case, remove instead the brake disc and the parking brake system.
1 - Lock nut and adjusting nut
2 - Pull rod
3 - Tab washer
4 - Retaining lug
6. In vehicles with automatic headlight beam adjustment, unscrew the strut from the angle sensor (on the left control arm (lower left arm)). Counter with a second open-ended wrench when doing this.
7. Undo stabilizer mount on the stabilizer. Counter with an open-ended wrench when removing from the stabilizer mount.
8. Push suitable protection over the drive shaft. Undo the drive shaft on the transmission.
9. Press drive shaft out of the wheel hub toothing.
Information
^ Since the drive shaft can be moved only using great force, loosen the shaft inwards with taps on a copper mandrel. Raise the shaft in the area of the inner joint (damage to the closure cap of the drive shaft possible). For unfavorable tolerances, the drive shaft must be pressed out of the wheel hub toothing using a universal wheel hub extractor (Fig. 42210004).
10. Press off tie rod ball joint on the wheel carrier using a commercially available ball joint extractor (tie rod extractor). When loosening the locknut, hold it with special tool 9546 (Torx screwdriver).
Information
^ Do not damage the boot of the ball joint when pressing off the ball joint If necessary, coat the boot and the ball joint extractor with tire mounting paste.
11. Loosen the outer ends of both upper arms and remove the screws.
12. Remove the ball joint from the control arm (lower arm). For pressing off the ball joint, use special tool 9560.
13. Loosen the spring strut on the wheel carrier (arrow) and remove the wheel carrier.
Installation
1. Install in reverse order. Before installing, visually inspect all parts. Replace self-locking nuts. Use correct tightening torques.
Information
^ When replacing wheel bearing housings (wheel carriers), pay close attention to the correct allocation. It is only permissible to install identical wheel bearing housings (wheel carriers) -- short or long steering arm (dimension X = approx. 124 mm or approx. 147 mm) -- on one vehicle!
Use of wheel carriers with the long steering arm -- in production -- partly in the current model year 1999 (X), but generally as of model year 2000 (Y).
Wheel carriers with a long steering arm -- dimension X = approx. 147 mm -- can be installed retroactively in pairs. For a detailed explanation -- for instance, parts which must also be used when converting a wheel carrier with a long steering arm -- see under "Replacing wheel carriers (after installation)".
X-Length of the steering arm
2. Grease the toothing of the drive shaft with Optimoly HT.
Information
^ Only optimized axle nuts - version B - for drive shaft fastening are available from the Parts Service.
A-Single-part fastening nut
B-Two-part fastening nut (moveable washer/arrows) SP No. 999 084 640 02 (status 09/99)
3. Fit the brake caliper. Replace fastening screws.
4. When installing the wheel carrier and tightening both the upper control arms, make sure that the spring strut fastening screw and the upper control arm fastening screws are only tightened in vehicle position. Vehicle position means: Vehicle standing on the wheels, or the wheel suspension is being raised with a universal lift.
Information
^ A calibration of the angle sensor of the headlight beam adjustment is not necessary.
5. Perform a suspension alignment after installation.
Replacing wheel bearing housings (wheel carriers)
Wheel carriers with a short steering arm (original version / dimension X = approx. 124 mm) and wheel carriers with a long steering arm (optimized wheel carriers) (dimension X = approx. 147 mm) are available from the Parts Service.
Use of wheel carriers with the long steering arm -- in production -- partly in the current model year 1999 (X), but generally as of model year 2000 (Y).
Wheel carriers with the short steering arm -- dimension X = approx. 124 mm -- will remain available.
The retroactive installation of wheel carriers with a long steering arm -- only in pairs -- is permissible! When installing wheel carriers with a long steering arm for the first time, the following parts must be used:
1. A differently shaped stabilizer (for reasons of space).
2. Optimized tie rods (toe control arms) with harder rubber mount.
In general, the following applies: Only wheel carriers (wheel bearing housing) of the same version - long or short steering arm (dimension X) - may be installed on any one vehicle.
A-stamped No. on the underside
X-length of the steering arm
A-stamped No. on the underside * of wheel carriers with short steering arm
Dimension X = approx. 124 mm
996.331.611. 05 / 996.331.612. 05
SP No. 996.331.111. 05 / 996.331.112. 05
A-stamped No. on the underside* of wheel carriers with long steering arm
Dimension X = approx. 147 mm
996.331.611. 06 / 996.331.612. 06
SP No. 996.331.111.06 / 996.331.112. 06
611 or 111 (7... 9 figure of the no.) = left section
612 or 112 (7... 9 figure of the no.) = right section
*The stamped number is missing on the underside of some wheel carriers in the initial series.
Information
^ Distinguishing features and spare part numbers of further parts to be used in first installation of wheel carriers with a long steering arm can be found in the text below.
1.Required stabilizer
The use of wheel carriers with a long steering arm is only permissible in conjunction with the following stabilizers:
^ 333.701. 16 = ± 18.5 mm (Production as of calendar week 26/99)
^ 333.701. 17 = ± 19.6 mm (Production as of calendar week 26/99)
^ 333.701. 20 = ± 20.7 mm (Production as of calendar week 36/99)
The allocation of stabilizers for the Coupe, Cabrio, manual transmission, Tiptronic, C4, M 030 can be found in the Spare Parts Catalogue.
Distinguishing feature/identification of the stabilizer models
1. Sticker (A) with the spare part number (SP No.)
2. Production date/calendar week (see text above) in conjunction with the outer diameter, insofar as the SP No. (sticker A) of the stabilizer is no longer legible. The production week (calendar week) is imprinted into one of the two flattened areas where the stabilizer mounts are fitted. Example: 26 9 imprinted. Corresponds to 26th week 1999 (week and year may also stand above each other).
A-sticker with the spare part number (SP No.)
2.Required tie rods (toe control arms)
The use of wheel carriers with a long steering arm is only permissible in conjunction with tie rods version B -- SP No. 996.331.045.10. It is only permissible to install these tie rods in pairs.
A -Tie rods without spherical mount
SP No. 996.331.045.06 / 07 / 08
Cast No. 996.331.245.06 / 07 / 08
B -Tie rods with the spherical mount (optimized tie rods with harder rubber mount).
SP No. 996.331.045.10
Cast No. * 996.331.245.10 (current) or
Cast No.* 996.331.245.083 (the 3 was stamped at the end of the cast number in order to distinguish it (arrow) and was additionally provided with a blue dot in this area).
On tie rod version B, the metal bushing of the rubber mount projects slightly -- by approx. 1 mm -- at both sides (arrow).