2002 Chrysler Concorde Brakes

When applying brakes most of the time there is 1 fairly loud thump. Brakes seem to be working adequately, no signs of brake fluid leaking. No squeaking or any other noise when brakes are applied. Front end is in alignment. No damage has occurred to front end or undercarriage. Had been driving about 400 miles per week, currently only driving on average 250 miles per week. This problem has started since driving less. Car is kept in a carport