I'm not saying that this is your problem, but it's worth checking. Try rocking the mudguard back and forth (front to rear) of the car. There should be no movement, but if there is......

The mudguard bolts on to a thick silver anodised plate and this plate worked loose on a friend's car. Getting to the four black hex socket bolts to tighten it back up was a bit of a pain because the hub, brake caliper & disc have to be removed to gain access.

[Linked Image]

Good news is that since tightening the problem hasn't reoccurred.

Last edited by Bunny; 11/09/19 08:13 AM.
Andy