When I started driving my '46 2-ton, the brakes worked great. It has had a brake job at some point in its recent history. The problem I'm having is that if the truck sits for a while, the pedal will go to the floor on the first pump. After that, it works fine. Plenty of resistance and I can lock the wheels on gravel at low speed. I have looked all over for leaks and found none. My mechanic couldn't see any leakage either. Once pumped up, it stops great and the pedal holds just like I would expect.
Now the question; what could cause this? The mechanic suggested adjusting the brakes, which I did, but it still happens on the first pump of the day. After that, it's fine. Could it be the master cylinder? The Hydrovac? Or is it just the system design?
Thanks for any information you can give.
