Brake issue

[drk]

I was driving my 66 289 3spd the other day when the brakes decided to go out on me. They were working just fine right before and were working (more or less) after they went out. The pedal would go to the floor with no pressure. The car started rough (because it was so cold). It's a bone stock 66. What should I check?

 

[gsxrken]

Probably time for a new master cylinder. They can internally leak, particularly when the o-rings are cold (think space shuttle), and fluid can bypass without building much pressure in the lines. Should be a cheap fix.

 

[rbohm]

i agree, time for a new master cylinder. my recommendation is to get a dual master from a 67 mustang to match your system(disc/drum or drum/drum). it is a bolt in master, but you will have to change the lines to allow for the dual master. i also recommend that you change the flexible lines as well since they are likely 41 years old anddue for replacement, about 15 years ago