Static on AM station when applying brakes
 

I drive a 2008 Mini Cooper Clubman. Has anyone experienced static on their radio while applying the brakes? This began happening on my car about 6 weeks ago when I played an AM radio station. The problem became worse: there was constant static on the AM radio station which would then go away when I applied the brakes. The shop replaced the radio and thought they had corrected the problem but it is still happening. Interestingly this problem does not occur when playing an FM station. Ideas? Suggestions?
Thanks.