The other day I noticed that it seemed like I had almost no rear brake stopping power. I don't use the rear brakes much except when coming to the final few feet at a stop sign or light. T thought that my pads might have glazed over so I took them off and sanded them on a flat surface. No difference. They aren't spongy and the rear brake fluid level hasn't changed. I can still lock the rear tire if I give it enough pressure, but there is no "feel" to it anymore. Is it time for a master cylinder or caliper rebuild?

I'm thinking about making a trip down to Ohio 555 before the season is done so I'd like to have everything back working before I go.