After I replaced the single reservoir master cylinder with a dual reservoir/booster kit I have had difficulty brakes remaining adjusted. I have 4 drums without discs so no proportioning value was needed. After adjusting for proper pedal height I experience a gradual decrease in pedal (tops out) until it can actually lock out the brakes. At that time if I readjust the push rod length so that the brakes are not locked out the pedal later will nearly go to the floor after the truck sits. I suspected that heat was a problem and shielded the lines from heat from the exhaust pipe. This didn't seem to help either. Any thoughts on this will be greatly appreciated.
