Brakes going to floor

MARTY ROBIN JACKSON

MEMBER
1999 SATURN SL1
2.3L
4 CYL
2WD
MANUAL
100,000 MILES

We replaced the clutch. Got everything put back and the brakes went to the floor. The car will stop but there is no pressure. Purchased a master cylinder. It did not come with seals. We have bled the brakes. Went through and checked all the lines. We do not know what else to do. Could we have purchased a bad master cylinder?

1 Reply

CARADIODOC

MECHANIC
33,742 POSTS

First you have to determine what caused the original failure. It could be as simple as a piston got pushed into a front caliper, and you had to run it back out by pushing the brake pedal. The pedal should never be pushed over half way to the floor. Crud and corrosion build up in the lower halves of the bores where the pistons do not normally travel. Pushing the pedal over half way runs the rubber lip seals over that crud and can rip them. That applies to any master cylinder more than about a year old, but not your new one.

Did you bench-bleed the new master cylinder? What seals are you referring to? Does your car have anti-lock brakes? If not, there is a simple trick when replacing the master cylinder that makes bleeding at the wheels unnecessary. GM front-wheel-drive cars have a valve in the master cylinder that trips and blocks two ports if you try to pedal-bleed with a helper. If air got in two of the lines, it will never bleed out if that valve got tripped. Gravity-bleeding is safer and will not trip the valve.