bamabucket
Member
We were preparing for a Sunday drive around noon today but had to cancel it when we had a total brake failure. The brakes were OK when I started the car and drove it out of the garage but when I stopped in the driveway the pedal went to the floor and I had no braking whatsoever. I don't have an external return spring but can pull the pedal up. When the pedal is depressed and returned by hand, I can feel quite a bit of resistance, but not the mushy feel I would expect with air in the system. I have done an external check for leaks and don't see any from any part of the system and there was fluid in both of the chambers of the master cylinder. I will check the wheel cylinders later but can't see any fluid that has leaked down and out between the drums and backing plates. In any case, a leak in a brake line or wheel cylinder shouldn't result in a complete failure because of the design of the dual master cylinder. My system is very basic with 4-wheel drums, no power assist, no proportioning valve, and no residual pressure valves. It looks like the most likely problem is a master cylinder failure. The master cylinder was replaced 5 years ago with the low-end generic unit Speedway sells. What I don't understand is how the master cylinder can fail completely with no evidence of leaks.
I haven't experienced this type of failure since the days of single chamber masters and that is why I have made this post to see if others have had similar experiences and can explain how this can happen.
The good part of the incident is that in happened in the driveway instead of in traffic and replacing the master cylinder is a very easy job.
I haven't experienced this type of failure since the days of single chamber masters and that is why I have made this post to see if others have had similar experiences and can explain how this can happen.
The good part of the incident is that in happened in the driveway instead of in traffic and replacing the master cylinder is a very easy job.