Knocking sound in the rain

[Ditch]

I had a similar issue. Upon investigation I found that there were plastic bolts that hold down the mud flaps inside the wheel arch that were loose. I simply tightened these by hand and the problem cleared

[Ditch]

I had a similar issue. Upon investigation I found that there were plastic bolts that hold down the mud flaps inside the wheel arch that were loose. I simply tightened these by hand and the problem cleared

[lnorange]

Known issue, drains in pillar, dealer fitted Volvo kit to correct, problem resolved