My Valiant has original 4 wheel drums 9" all 4 wheels. I noticed the master cylinder behind the pushrod boot has some wetness, the stoplight switch is stuck. I checked the rear on one side because the E-brake doesn't hold and I noticed the self-adjuster cable was broken and fell out. The brakes actually stop really good. It's got a good pedal. Parts are still available to rebuild the drums system. Is this system adequate for occassional driving? Do they make a direct bolt on line kit for swapping to a dual master cylinder? I don't want to have to bend any lines. How often do the single port master cylinders totally all out fail and everything goes out going 70mph? I know that I've seen many bigger and more powerful restored cars at car shows with guys still running a single port master cylinder. I just want to know what I should do to restore my brake system. Thanks.