Gentlemen, Is there any hope or repair possible for a front brake caliper short of replacing the caliper. I purchased a used caliber not too long ago, but with a new piston seal installed, it still leaks when pulling the brake lever after filling with brake fluid and bleeding the caliper. I then checked the brake piston with a micrometer and checked for defects in the piston surface and found it to be in good shape. However; during examination of the internal caliper surfaces, I did note that the slot that the piston seal sits in was somewhat rusty.
I took the caliper with piston and another new seal to one of the local motorcycle repair shops and after explaining the situation, asked them to clean the caliper and reinstall with the new piston seal. When I picked up the (cleaned) caliper I asked him about the rust in the seal seat and was informed that he used a flattened motorcycle spoke to scrape out the visible rust in the seat.
After reinstalling the (cleaned) caliper on the bike, it now leaks more that it did prior to cleaning. I suspect that the shop possibly removed too much of the seal seat surface allowing brake fluid to seep around the bottom and perhaps the sides of the seal.
I don’t know if it’s possible or even been attempted in the past, but is it feasible to perhaps add some type of sealant to the ring seat, reinstall the ring seal, scrap off any residual sealer from around the outside edges of the ring seal, reinstall the brake piston and let the sealant firm up prior to adding brake fluid and attempting to use the caliper. Any thoughts or ideas would be greatly appreciated. Tks
