should I use any lubrication on the piston seal? it fits inside the body of the caliper and around the outside of the piston. use brake fluid? use a light grease? use nothing. these brakes have never worked right. the inboard pad will not retract away from the rotor. bleed after bleed and it operates the same. I searched here and the SRAM site and found nothing. a link to a parts list would be helpful. I only have one rebuild kit, no part number on it. thanks.