Got in for a cruise today - been about 4 weeks since last driven - and the brake pedal went to the floorboard. It didn't fall, just slowly went all the way. Looked at the brake master cylinder and found the front rubber distorted and the chamber low on fluid - maybe 25% low. No sign of leaks at any wheel or the master cylinder. Any suggestions what the problem or solution may be?

If there are no signs of leakage at the wheels/calipers, the master is most likely leaking. Take the master loose from the booster(or firewall, if no power brakes), and look for fluid at the end of the master. If there is fluid present, the master is leaking, and will need to be rebuilt/replaced. If you have power brakes, and the master is leaking into the booster, the fluid will eventually eat away at the rubber diaphram in the booster. With NO power brakes, a quick look under the dash, where the brake push-rod goes thru will show fluid running down the firewall/floor(if the master is leaking)

If there is no fluid at the end of the master, then the master will probably be leaking internally, and will still need to be replaced/rebuilt. Sometimes, with an internal leak, the fluid will travel from one side of the master reserviour to the other, resulting in one side being low, and the other being very high.

Check around the wheels/calipers very carefully tho. A small leak at a caliper may not be easily seen.

As Joel said...check everything closely. Don't discount a small leak that not's visible yet at the wheels.

Earlier this season I was on my way to a cruise-in in my '69 (Riverside Gold like yours). When I was on the way and stopped at a sign, my BRAKE light came on...only two reasons for that...either my parking brake was engaged or something else more serious. Well...my parking brake was not engaged. One chamber of my master cylinder was empty. The left rear caliper seal blew out and the inside of the wheel and that area was soaked in brake fluid.

I was able to drive the car home carefully with the front brakes operating, and the repair was straightforward.

Hope fixing yours is as straightforward. Good luck.

Jim - if you're not comfortable working on the brakes yourself I'd recommend calling Ray Graver at the Twin City Tire location on Lyndale Ave South in Bloomington.  If you need to get your car some where and don't want to drive it let me know and I can come over with my trailer.

Jim: