Brake pedal goes fast and easy to floor

LILYPIE1983

MEMBER
1991 FORD EXPLORER
4.0L
6 CYL
2WD
MANUAL
58,000 MILES

Push brakes and they barely work. They go straight to floor with ease. Fluid level drops very fast to nearly empty within short period. When finding where the leak was coming from, it doesn't leak until the pressure is released from pumping brakes and seems to be leaking from bottom of break booster. What do I need to do?

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon,

Sounds like the master cylinder is leaking into the booster.

I would replace the master and the booster and bleed the lines.

Roy

Master

WITH POWER BRAKES

1. With engine off, depress brake pedal to expel vacuum from brake booster system.
2. Disconnect hydraulic lines from master cylinder.
3. Remove brake booster to master cylinder retaining nuts and remove master cylinder from brake booster.
4. Reverse procedure to install and perform system brake bleeding procedures, then refill master cylinder and bleed it.

LESS POWER BRAKES

1. Disconnect wires from stop light switch inside cab below instrument panel.
2. Remove retaining nut, shoulder bolt and spacers which secure master cylinder pushrod to brake pedal assembly, then remove stop light switch from pedal.
3. Disconnect hydraulic brake lines from master cylinder, then remove master cylinder to dash panel retaining nuts, master cylinder, and boot from master cylinder pushrod.
4. Reverse procedure to install and perform system brake bleeding procedures, then refill and bleed master cylinder.

Image (Click to make bigger)