Knocking sound when braking slowly
Over the past few weeks, my car has been making a knocking sound every time I brake. I don't hear it at all when I am moving more than 20mph and I believe it makes the sound once every revolution of the wheel. The sound seems to get louder the warmer the engine is as I can't seem to reproduce the loud knocking sound when I drive from a cold start.
I did have a clashing sound when going over bumps and found that the lower brake pad retention spring was missing. After fitting the spring, the clashing sound has disappeared but the knocking noise is still there.
I had a mechanic do a basic check under the car to see if anything was loose but he found nothing besides the brake pad spring.
Has anyone else experienced anything similar or know what's going on? Any help would be greatly appreciated!