The Stovebolt Site Forums The Parking Lot Big Bolts 1946 Two Ton Front Brake Adjustment

Not only does there need to be room in the master cylinder for brake fluid to return to the reservoir, but the pedal pushrod needs to be adjusted so that the relief opening is uncovered when the pedal is released. If the relief opening is obstructed, expanding brake fluid (from heat) won't have anywhere to go and will expand the wheels cylinders and lock up the brakes. If you push the pedal while observing the fluid in the reservoir, you should see a little fluid being pushed back into the reservoir in a little geyser. That's the fluid being released before the master cylinder cup covers the relief opening and begins expanding the wheel cylinders.