Mine were leaking and I had no idea about it until a guy told me. Ended up costing me more cache cause I had to have the brakes rebuilt and new pads put in to replace the new pads I had put in several thousand miles ago. I bought that Sealmate tool but didn't try to use it. When I was dropping the bike off at the shop I asked my mechanic about it and he says he tried it but it didn't work worth a crap! I've read others from this forum have used it with satifaction so I'm confused. ???