BMW E39 front end rattle at low speed
What causes the E39 front end rattle at low speed?
The most common causes are a loose thrust arm ball joint, worn control arm bushings and ball joints, anti-roll bar bushings, the top of the shock absorber and the drop links. The anti-roll bar bushings and drop links are cheap and easy to replace, and they should be checked when replacing the shock absorbers.
How do I locate the source of the rattle when I cannot find anything loose?
Play in the thrust arm usually does not show on a lift or when prying, only once the control arms have been removed. The top of the shock absorber is found by lifting the tyre vertically. If the rattle disappears when braking, the cause can be the thrust arm or a loose brake pad. Replace the thrust arm as a whole, not just the bushing.
What else besides the suspension can rattle behind the wheel?
Stones left behind the brake shield rattle on cobblestones, and they are found by removing the tyre and shining a light upward from underneath. A dragging brake shield or a loose brake pad also makes noise. If a new bushing is the wrong size, it can end up loose in the mounting fork.