All 3 grooves was filled with old grime. I sand blasted the caliper housing, but only gently scraped the grooves for the piston seal and dust cap. The groove for the seal between the e-brake was incredibly full of crap. As the picture shows the O-ring is forced out of the groove. With the caliper body blasted, and new O-ring greased up with dow 55 O-ring grease it looked awsome
