BMW E38 front end knocking and clunking
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What causes knocking and clunking in the E38 front end?
The most common cause is play in the thrust arms (the bushings go soft) or in the lower control arm ball joint. The anti-roll bar links, also called sway bar links, and a worn tie rod joint also knock on an uneven road.
What should you replace first when the front end knocks?
Sway bar links are cheap to replace, so do them first. Thrust arms are replaced on both sides and as the whole arm, not just the bushing. Wheel alignment is mandatory after replacing a tie rod.
Why does an E38 knock on cobblestones, but the knocking stops with light braking?
The cause can then be a metal support spring behind the brake pad that has broken and rattles in the caliper. Another possible cause is play in the lower ball joint of the lower control arm, which shows up when the front is raised from the center beam.
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