31 31 041 Replacing front left or right spring strut (M3)
Special tools required:
- 31 3 340
- 31 3 341
- 31 3 351
All the safety precautions and instructions contained in the Owner's Handbook must be strictly observed!
Failure to observe these safety precautions and instructions increases the risk of serious physical injury, damage to your health and damage to property and equipment!
- Prior to each use, check the special tools for defects, modifications and operational reliability.
- Damaged/modified special tools must not be used!
- No changes or modifications may be made to the special tools!
- These special tools are intended solely for the purpose of tightening and relieving cylindrical and tapered suspension springs.
- Keep special tools dry, clean and (down to the spindle) free from grease.
- The use of an impact screwdriver on special tool 31 3 341 is prohibited!
- Do not compress coil spring to full extent.
Necessary preliminary tasks:
- Remove front spring strut
Removing:
Clamp special tool 31 3 341 in vice.
Fit special tools 31 3 351 from above on special tool 31 3 341 until locking pins (1) can be felt and heard to snap into place.
Check seating of special tools 31 3 351 , correct if necessary.
Clean coil spring to remove all coarse dirt and mount on special tools 31 3 351 .
Turn spring strut until lower end of coil spring (1) points upwards.
The upper and lower coils of the coil spring must be situated entirely in the recess of special tools 31 3 351 .
Compress coil spring until stress on piston rod is relieved.
Nut may only be released if:
- the coil spring has been sufficiently tensioned with special tools 31 3 341 and 31 3 351
- the upper and lower coils of the coil spring are situated entirely in the recess of special tools 31 3 351
Release nut (1) (grip piston rod in so doing) and remove support bearing (2).
Ensure conditions of absolute cleanliness when handling the two-part support bearing.
Pull off thrust washer (1) and auxiliary damper (2) with gaiter (3) from piston rod of shock absorber (4).
Remove shock absorber (4) sideways from coil spring.
Relieve tension on coil spring and remove from special tools 31 3 351 .
Assembly:
The lower coil of the coil spring is slightly smaller than the upper coil.
Accommodate coil spring with special tools 31 3 351 .
Turn coil spring until lower end of coil spring (1) points upwards.
Do not compress coil spring to full extent.
The upper and lower coils of the coil spring must be situated entirely in the recess of special tools 31 3 351 .
Tension coil spring.
Replace spring pad (1).
Check auxiliary damper and gaiter for damage, replace if necessary.
Insert shock absorber (4) in tensioned coil spring.
Slide auxiliary damper (2) with gaiter (3) onto piston rod.
Attach thrust washer (1) to piston rod.
Replace spring pad (1).
Check support bearing (1) for damage, replace if necessary.
Attach support bearing (1) to piston rod.
Coat mounts (2) with Circo Light (sourcing reference: BMW Parts Service).
Attach joint plate (1) to piston rod.
Replace nut (2) and tighten down (gripping piston rod in so doing).
Tightening torque 31 31 2AZ , see 31 31 SPRING STRUTS
Lower end of coil spring (2) must rest on stop of spring pad (1)!
Relieve tension on coil spring.
Check installation position of gaiter (3), correct fold if necessary.
After installation:
- Carry out wheel alignment check if a spring strut with support bearing was or has been installed without centering pin. See 32 00 150 KDS CHASSIS/WHEEL ALIGNMENT CHECK WITH LOAD UP TO DESIGN POSITION or 32 00 155 KDS CHASSIS/WHEEL ALIGNMENT CHECK WITH RIDE-HEIGHT MEASUREMENT WITHOUT LOAD .