Took my just finished 40' chev half ton out for it's second ride. Brake peddle went the floor! Had the master clinder "rebuilt" by an "expert" not long ago.It lasted about 5 miles. Fortunately, I was going slow on a back road checking everything out.No accident. That truck won't move til it has a dual master on it. The rebuilt 261 runs GREAT tho.Be careful out there.