Recentley replaced the driver side backing plate on my rear drum brakes

no fun, got a backing plate off a 69 cheby chevelle from a friend and it worked great ...installed and test rode..worked fine ,,,was loading on trailer to go racing this evening and lo and behold i hears a squeaking noise coming outa the pass. side rear brakes, so i pulls the wheel off and what do i find but bent brake pads. kinda odd huh....anyone know why this happened ???? Ill give yall some time to think on the matter....I figured it out this evening after i fixed the other side but lets see what yall think [img]tongue.gif[/img] well at least its what i THINK caused it
Mike