ABS System Components on Front Axle, Removing and Installing

ABS system components on front axle, removing and installing





Note: Removing and installing ABS system parts is identical for FS III and FN 3 brake calipers.

1- ABS speed sensor
^ Before inserting sensor, clean mounting hole inner surface and coat with lubricating paste G 000 650
2- Wheel bearing housing
3- Hex socket head bolt, 8 Nm (70 in lb)





4- Splash plate
5- Hex bolt, 10 Nm (62 in. lb)
6- Wheel bearing
^ Replace each time after removing
7- Phillips-head screw
8- Brake disc
9- Wheel hub with rotor
10- Circlip

Removing and installing speed sensor on front axle

Removing
- Raise vehicle.





- Disconnect speed sensor and speed sensor wiring connector -1-.
- Remove bolt -2- from wheel bearing housing.
- Pull ABS speed sensor from wheel bearing housing.

Installing
- Before inserting speed sensor, clean mounting hole inner surface and coat speed sensor with solid lubricant paste G 000 650.
- Insert speed sensor into mounting hole in wheel bearing housing and tighten bolt to 8 Nm (71 in. lb).
- Connect speed sensor to speed sensor wiring connector.
- Turn wheels fully left and right lock and check clearance to speed sensor wiring.

Checking or removing and installing rotor on front axle
- Raise vehicle.
- Remove wheel.
- Rotate brake disc and check rotor is damaged or dirty.
- If rotor is damaged, remove wheel hub with rotor and replace.

Checking rotor lateral run-out
- Raise vehicle.
- Remove wheel.





- Turn wheel hub and check gap -dimension a- between rotor and speed sensor is even.
Dimension a = 0.3 mm (0.0118 in.)
- If rotor is damaged, remove wheel hub with rotor and replace.

Front speed sensor wiring, removing and installing

Special tools and equipment





^ VAS 1978 Wiring harness repair set

Removing:
- Obtain radio code on vehicles with coded radio.
- Disconnect battery.





- Release control module connector (arrow -1-) and pull off (arrow -2-).





- Release multi-pin connector cover cap with a screwdriver and remove.





- Release secondary locking device (violet) in direction of arrow with a screwdriver.





ABS/EDS/ASR/ESP Mark 60 connector T47

Contact assignment of connector T47 wiring harness/ABS control module (w/EDL) -J 104-.





- Push out relevant contacts with an ejection tool from wiring harness repair kit VAS 1978.
- Separate connector from speed sensor wiring and speed sensor.





- For vehicles with brake wear indicator separate connector -1-.
- Unclip the wiring from retainer -2-.
- Remove faulty speed sensor wiring and guide in new speed sensor wiring.
- Connect speed sensor to speed sensor wiring.





- Clip in speed sensor wiring (arrows).
Make sure the wiring is not twisted when installing the speed sensor wiring in the wheel housing.
- Insert brake wear indicator connector into bracket on suspension strut.
- Guide contacts into connector housing.





- Push individual wiring seals in onto stop with an insertion tool from VAS 1978.
- Secure contacts with secondary locking device and install multi-pin connector cover cap.

Speed sensor on front axle, removing and installing

Removing
- Raise vehicle.





- Separate speed sensor and speed sensor wiring connector -1-.
- Remove bolt -2- from wheel bearing housing.
- Pull ABS speed sensor from wheel bearing housing.

Installing
- Before inserting speed sensor, clean hole inner surface and coat speed sensor all-round with solid lubricant paste G 000 650.
- Insert speed sensor into hole in wheel bearing housing and tighten bolt to 8 Nm (71 in. lb).
- Connect speed sensor to speed sensor wiring.
- Turn wheels fully onto left and right-hand lock and check clearance to speed sensor wiring.

Rotor on front axle, checking or removing
- Raise vehicle.
- Remove wheel.
- Rotate brake disc and check rotor is not damaged or dirty.
- If rotor is damaged, remove wheel hub with rotor and replace.

Checking rotor lateral run-out
- Raise vehicle.
- Remove wheel.





- Turn wheel hub and check gap dimension -a- between rotor and speed sensor is even.
Dimension a = 0.3 mm (0.0118 in.)
- If rotor is damaged, remove wheel hub with rotor and replace.

Front speed sensor wiring, removing and installing

Special tools and equipment





^ VAS 1978 Wiring harness repair set

Removing
- Obtain radio code on vehicles with coded radio.
- Disconnect battery.





- Release control unit connector (arrow -1-) and pull off (arrow -2-).





- Release multi-pin connector cover cap with a screwdriver and remove.





- Release secondary locking device (violet) in direction of arrow with a screwdriver.





ABS/EDS/ASR/ESP Mark 60 connector T47

Contact assignment of connector T47 wiring harness/ ABS Control Module (w/EDL) -J104-





- Push out relevant contacts with an ejection tool from wiring harness repair kit VAS 1978.
- Separate connector from speed sensor wiring and speed sensor.





- For vehicles with brake wear indicator separate connector -1-.
- Unclip the wiring from retainer -2-.
- Remove faulty speed sensor wiring and guide in new speed sensor wiring. Connect speed sensor to speed sensor wiring.





- Clip in speed sensor wiring (arrows).
Make sure the wiring is not twisted when installing the speed sensor wiring in the wheel housing.
- Insert brake wear indicator connector into bracket on suspension strut.
- Guide contacts into connector housing.





- Push individual wiring seals in onto stop with an insertion tool from VAS 1978.
- Secure contacts with secondary locking device and install multi-pin connector cover cap.