hissing? from rear whilst braking.

[BRUCEY]

my mate has a 54plate 1.2 clio. hes recently noticed a hissing noise from the rear of the car at both sides whilst braking. sort of like air escaping from somewhere. the braking isnt affected in any way.

any ideas?

and no there isnt a snake in the boot that doesnt like slowing down.

 

[minisuper666]

probably your brake pads wore down to the point of rivets contacting the drum

 

[BRUCEY]

anyone else have any ideas. ta.