Brake pedal goes to the floor brakes won't stop

Tiny
KTWEETY
  • MEMBER
  • 1989 MERCURY TOPAZ
  • 240,000 MILES
We have replaced master cylinder, front and rear brakes, calipers, cylinders and brake lines in the rear and bleed them still no brakes?
Thursday, September 27th, 2012 AT 5:09 PM

6 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Something has not been done correctly. When bleeding the system are you getting pressure at all wheels?
Are you able to get pedal pressure when bleeding?
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+1
Thursday, September 27th, 2012 AT 5:22 PM
Tiny
KTWEETY
  • MEMBER
  • 3 POSTS
We are getting good flow from the dr front and pass rear but only trinkles from the dr rear and pass front. Before we changed the master cylinder it was opposite.
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Thursday, September 27th, 2012 AT 5:44 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
System uses diagonal braking lines so one of the master cylinder circuit is not working correctly.

If you did not bench bleed the master cylinder, I would suggest starting from there. Get someone to slowly depress the brake pedal a few times and hold the pedal in a depressed position with about 10 psi of force, meaning the foot should not be held too heavy on pedal. Crack the inner line of the master cylinder and if fluids comes out without any bubbles, repeat with the other line.

Next we go on to the wheels and the bleeding sequence is Right Rear, Left Front, Left Rear, Right front. Do this with engine off.

If you are still having problem with insufficient pressure with Left Rear and Right Front lines, loosen the master cylinder holding bolts by 3 turns and repeat process. If it works, check the brake pedal and booster adjustment.
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Thursday, September 27th, 2012 AT 6:31 PM
Tiny
KTWEETY
  • MEMBER
  • 3 POSTS
Thank u we will try that
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Thursday, September 27th, 2012 AT 6:55 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Any updates?
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Sunday, October 21st, 2012 AT 5:09 AM
Tiny
STRIPPEDKNUCKLES
  • MEMBER
  • 2 POSTS
Got a 92 topaz with the same issue. Got fluid on the passenger side but nothing on the driver side. Has a new master but doesn't really seem to get enough pressure on the pedal.
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Sunday, November 2nd, 2014 AT 5:29 PM

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