I have been driving my 71 daily for over three years now with no real problems at all. The other day I stepped on the brake pedal and there was no longer any tension against the pedal until it just about hit the floor, and then the brakes locked up on me.

So when I step on the pedal instead of hitting resistance after just barely pushing down on it, and the brakes gradually applying as I increased pressure - it now goes down about 4-5 inches with NO resistance at all, then the brakes just about lock up - there is no gradual braking anymore - it's all or nothing.

My thought is the master cylinder has gone bad, but I would like to hear from anyone else who may have some idea before I go spend money on parts.

Thanks to all who may respond - I do appreciate the time you spent.

 

Have you checked the obvious?, is the M/C nearly empty?, could be a leaking wheel cylinder or brake pipe.

Before you part with any money for a new M/C take the wheels and drums off and check if anything is amiss.

Roger.

 

Start with the basics- ck MC fluid level and bleed 'em.

 

If the M/C were the problem, I doubt the wheels would lock up. My money is on the booster.

 

I did check obvious stuff - I should have said that in original post. Not low on fluid - no wet inside any of the drums - no obvious broken lines under car - no leaking that I can see anywhere. I did not re-bleed the brakes though.