My piston is really chewed up where it contacts the pad. 1/8" rough grooves due to imbedding into the drilled holes in the metal pad casing. Should I have put a shim in between?

Is it hard to replace the piston?

Thanks

 

Not too hard with a manual and compressed air.

 

i'am lost on your story here ?
1- pads worn out?
2-rotor all bitched?
3-piston on caliper should be ok ? or are the pads worn that far down they went into the backing plate of the pad?

just trying to help here.

 

The caliper piston where it makes contact with the pad has grooves chopped into it. The metal part which holds the pad has three 1/2" manufactured holes in it. I guess the piston dug into these holes?

 

ok, new pads should have shim plates on there outer side.
i think these are stainless