I have 2003 BMW 530i. Dealership said some time ago that control arm bushings needed to be replaced but I was dubious and did not have them replacement. More recently the car doesn’t recover well from potholes and shakes a lot, especially when hitting a bump at low speed. Is shaking likely related to control arm bushings, and what happens when control arm bushings are worn?
The control arms are the pivot points that the steering knuckles are attached to that allows the suspension to move up and down. At the point where the control arms are attached to the craddle/subframe are the pivot points, and at these pivot points are the bushing. When the bushings wear out, the control arms no longer pivot in a single plane but instead can wobble. A good example is take a worn out hinge, and hold one leaf down flat on a table while the other leaf is allowed to hang over the side. With a good hinge, the leaf can be moved up and down in one plane without wobbling. With a worn hinge the leaf can wobble as it’s moved up and down. This same thing happens with worn out control arm bushings.
What happens when bushings wear out? The tires will wear out faster because the alignment is no longer being held, and it accelerates wear and tear on other steering/suspension components.
Tester
Yes these bushing can wear,I have put them in before,earlier 5 series were much worse. Unlike shocks (which I think you should also consider) control arm bushings can be inspected visualy and a definite conclusion as to their condition made.