[dynamic88]

i have a 65 olds dynamic 88 convertable. last year i replaced all the brakes from the master cylinder down to the brake cylinders. the lines were bled off and everything. on two seperate occassions i have went to pull the car out of the garage and did not have any brakes. when i checked the master cylinder i found it to be empty wheni filled it up i had brakes again. i have checked the brake cylinders, the lines there are no signs of a leak. any suggestions on where it might be going. thanks chris