LeSabre brake issues

1995 Buick LeSabre 3.8 93,000 miles
Has _ABS_

Hi all. I'm helping my friends with her buick. I've test driven and at different times the pedal goes to the floor with ease, with only the drum's being used. (This was verified with vehicle in drive on jackstands) Sometimes the pedal operates normally, as in firm and all four wheels stopping correctly. During the times it goes to the floor, the drums engage very sharply.

There's plently of brake fluid and I see no leaks. Power booster seems to be operating correctly, and there is vacuum to it.

Given all these symptoms, I picked up a master cylinder to replace this one. Anyone have an ideas on what else this could be? No Brake or ABS lights illuminate. Pads and rotors look fine.

Thank you in advance.

http://www.websmileys.com/sm/fingers/fing10.gifI think you have the problem identified. Also, be sure to flush all the old fluid out of the calipers when bleeding the system.

alright cool. wish me luck with the bleeder screws :/ their rusted.

alright cool. wish me luck with the bleeder screws :/ their rusted. Good Luck With the Bleeder Screws:rofl:
Let the bleeder screws soak in PB Blaster for a few hours, before trying to turn them!:iceslolan

just an update everyone-It went really well. Replaced master cylinder/bled it at all four wheels and the brakes are normal again. Thanks for your help.

"I Love It When A Plan Comes Together!":grinyes:
George Peppard , (Col. Hannibal Smith) from TVs “The A Team"