1999 Peugeot 106 1.4 XS, Knocking coming from front driver side wheel when slowing down to about 15-20mph and below. The knock sounds like 'du dum du dum du dum du dum' and doesnt occur when turning corners etc just when slowing to a stop even without applying brakes. No vibrations through the pedals or the steering wheel. Any Idea what this could be?