anyone know why the rear brake anti squeal shims on an 09 sti only cover half of the piston? they are diagonally shaped so that half of the piston is against the pad, but the other half is in contact with the shim. the only reason i can think of is so that it creates a slight taper on the pad surface. Are they actually needed as new pads do not come with new shims. Any explanations would be welcome! cheers, steve.

 

you clean and re-use the "squeel" shim............its tapered because its designed to work in a rotational direction and they have always been that way for the Brembo's in particular

 

Got these on my05 Wrx aswell. They squeal without em.