The Stovebolt Site Forums The Parking Lot Big Bolts Need help troubleshooting brake issue

I have a 1966 C60 firetruck that I parked about 15 months ago with everything working. Today I cranked it up and the brake pedal goes all the way to the floor without any resistance. Any ideas to help me troubleshoot the issue?

First check the fluid in the master cyl. It is probably empty. Fill it with brake fluid & pump it many times. It will probably build up a pedal. Then you need to find were the leak is. It could be going into the power unit.

if the m/c is dry there should be plenty of evidence of where it went. look on the inside of the tires at 6 clock position no signs of wetness you can bet the booster absorbed it. with it running and when you press on the brake does the tail pipe emit pretty blue smoke? if so that's the brakes fluid being drawn into the engine and burned. another way to tell is on a bendix type unit is to disconnect the vacuum line from the carb at the unit. if fluid runs out the unit needs repair or replacement.

Quite often the seal may be out on the hydrovac piston and just leak into the chamber, not making it to the engine right away.