: Brake Pedal Floors on Decelerate



jennings3
07-20-11, 12:34 PM
'79 Fleetwood Brougham has been in the family since new, sits at mother's and driven on weekends. It is a beautiful car that I have to sell because I was laid off. The brakes were serviced about six months ago. Because of no income I need to try to fix this myself, if I can. I have changed pads/rotors on my other car, Ford Taurus but it is a lot newer (2002).

The brake pedal seems firm, then on slowing it suddenly goes to the floor. Sometimes seems like it happens on downshift. Other times I will be stopped and the car will roll forward, scary. Now it is parked but Taurus is in the shop so I don't have transportation.

I searched threads for a while and could not find a similar problem on a previous post. Please help with your suggestions. Many thanks, wjs

turbojimmy
07-20-11, 03:17 PM
'79 Fleetwood Brougham has been in the family since new, sits at mother's and driven on weekends. It is a beautiful car that I have to sell because I was laid off. The brakes were serviced about six months ago. Because of no income I need to try to fix this myself, if I can. I have changed pads/rotors on my other car, Ford Taurus but it is a lot newer (2002).

The brake pedal seems firm, then on slowing it suddenly goes to the floor. Sometimes seems like it happens on downshift. Other times I will be stopped and the car will roll forward, scary. Now it is parked but Taurus is in the shop so I don't have transportation.

I searched threads for a while and could not find a similar problem on a previous post. Please help with your suggestions. Many thanks, wjs

Check the brake fluid level. Sounds like you have a leak somewhere. Eventually it won't stop at all.

If the level is low, inspect the lines at each wheel for leaks as well as all of the lines from the master cylinder to their ultimate destinations. I'd bet on a rusted/popped line somewhere.

drmenard
07-20-11, 03:50 PM
First I would check the inside of all the tires for brake fuild to see if there is a wheel cylinder leaking then look for drips from a bad brake line. If no leaks and it feels like you have brakes and then they are gone and you pump it again and they feel like they are back I would think that the seals in the mastercylinder are leaking...

turbojimmy
07-20-11, 04:08 PM
First I would check the inside of all the tires for brake fuild to see if there is a wheel cylinder leaking then look for drips from a bad brake line. If no leaks and it feels like you have brakes and then they are gone and you pump it again and they feel like they are back I would think that the seals in the mastercylinder are leaking...

Good point. Could be the MC leaking into the car.

jennings3
07-20-11, 04:15 PM
it feels like you have brakes and then they are gone and you pump it again and they feel like they are back I would think that the seals in the mastercylinder are leaking... That's exactly the way it behaves and there appears to be plenty of fluid in the reservoir. I have never dealt with a master cylinder though I've done pads and rotors a few times. Is master cylinder very difficult? Thanks much for the replies.

turbojimmy
07-20-11, 09:25 PM
That's exactly the way it behaves and there appears to be plenty of fluid in the reservoir. I have never dealt with a master cylinder though I've done pads and rotors a few times. Is master cylinder very difficult? Thanks much for the replies.

The master cylinder isn't a bad job. You need to follow the bench bleeding instructions, and then may have to bleed the system afterward. I've done them where the bench bleeding is enough, and others where I need to bleed the system at each wheel as well. If you do have to bleed them at the wheels, you may run into some sticky bleeders which could lead to having to replace a caliper or wheel cylinder.

jennings3
07-22-11, 04:17 PM
This one is over my head and I better take it to the shop. Many thanks for your help.