Front Steering Knuckle: Service and Repair

31 21 090 Replacing (Removing And Installing) Left Or Right Swivel Bearing (M3, M Coupe)

Special tools required:







IMPORTANT:
To ensure an optimal power transmission from the swivel bearing to the spring strut, the special tool 31 5 230 must be used for the installation on the spring strut.
Special tool 31 5 230 may only be removed after the screw connection is applied.







Necessary preliminary tasks:
- Remove front brake disc.







Slacken nut (1).
Tightening torque 37 14 3AZ.
Remove jointed rod (2) from left wishbone.

Installation note:
Sensor lever (3) must point from ride height sensor to left front wheel.







Remove wishbone from swivel bearing.
Remove track rod end from swivel bearing.
Remove trailing link from swivel bearing







Support swivel bearing with workshop jack and suitable fixture.
Release nut (1), remove screw (2) and
remove holder (3).
Tightening torque 31 31 3AZ.

Installation note:
Replace self-locking nut.
Screw head must point in direction of travel.







Release screw (1).
Tightening torque 34 51 4AZ.
Remove pulse sensor (2) from the swivel bearing.

Installation note:
Clean bore hole for pulse sensor and grease with Staburags NBU 12/K lubricating grease (refer to BMW Service Operating Fluids).







IMPORTANT:
Expand swivel bearing below the screw feed-through to prevent damage to the swivel bearing.
Expand swivel bearing with special tool 31 2 230.
Lower workshop jack and remove swivel bearing.

Installation note:
Keep press fit of swivel bearing and spring strut in lower area clean and free from oil and grease.







IMPORTANT:
Align special tool 31 5 230 as shown to ensure a correct installation on the swivel bearing.
Special tool 31 5 230 may only be removed after the screw connection is applied.

Installation note:
Expand swivel bearing with special
tool 31 2 230, align based on gap to bridge
1. on rear side of spring strut and push
upwards.
Pull swivel bearing to limit position (tightening torque 20 Nm) using special tool 31 5 230.

Remove special tools 31 2 230.







Replacement:
- Modify wheel bearing
- Modify brake anchor plate/brake guard plate.







After installation:
- Replacement: Carry out wheel alignment procedure.