BMW F10 front end rattle and lower control arms
What usually causes a BMW F10 front end rattle?
The most common cause is the outer ball joint of the transverse lower control arm. Another common cause is softened hydro bushings of the thrust arm, which are felt as clunking at junctions and when braking. The anti-roll bar link and the nut at the top of the shock absorber can also rattle.
How do I find front end play when nothing was found at the annual inspection?
Ball joint play is vertical, so it does not show when rocking the wheel sideways. Lift the wheel quickly up and down, which reveals the play. Sometimes the play can only be felt once the part has been removed or the car is fully in the air.
Which parts should be replaced at the same time and what is done afterwards?
When one bushing is loose, the others will soon loosen too, so it is worth replacing the lower control arms and thrust arms together. After the replacement the car is taken for a four-wheel alignment. Bolts and nuts are replaced with new ones.