Sounds like air in the system to me, too. 
'79 brake problem.....HELP!
Thread Starter
Pro
Joined: Aug 1999
Posts: 514
Likes: 0
From: Roseville California
'79 brake problem.....HELP!
My brake pedal goes to the floor.
I have replaced the pads, rebuilt the calipers, new master cylinder, and YES I BLED the daylights out of the brakes. The brakes will stop you, but you can push the pedal far enough to touch the floor, and the brake warning light comes on.
I need some good ideas, my wife is upset that she can't drive it, and the nagging needs to stop....
I have replaced the pads, rebuilt the calipers, new master cylinder, and YES I BLED the daylights out of the brakes. The brakes will stop you, but you can push the pedal far enough to touch the floor, and the brake warning light comes on.
I need some good ideas, my wife is upset that she can't drive it, and the nagging needs to stop....
Instructor
Joined: Dec 2007
Posts: 150
Likes: 0
From: Orrville Ohio
just replaced a caliper on mine had a bad piston and now they are better, i would check for leaks take calipers off and check the pistons. you can rule out power booster if thats what it was it would be really stiff pedal. then if no leaks go for the master cylinder.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
My brake pedal goes to the floor.
I have replaced the pads, rebuilt the calipers, new master cylinder, and YES I BLED the daylights out of the brakes. The brakes will stop you, but you can push the pedal far enough to touch the floor, and the brake warning light comes on.
I need some good ideas, my wife is upset that she can't drive it, and the nagging needs to stop....
I have replaced the pads, rebuilt the calipers, new master cylinder, and YES I BLED the daylights out of the brakes. The brakes will stop you, but you can push the pedal far enough to touch the floor, and the brake warning light comes on.
I need some good ideas, my wife is upset that she can't drive it, and the nagging needs to stop....
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I think you may have a suspect master cylinder or air in the lines. I know you said you bled and bled, but air can sometimes be caught IN the master and IN the calipers in large pockets.
Try bleeding again, but this time use check valve bleeders that don't let air in around the threads, and tap the calipers and master with a wooden handle to dislodge any air bubbles.
If that doesn't help then I would remove the master, rebuild it, and try again after bench bleeding.
Try bleeding again, but this time use check valve bleeders that don't let air in around the threads, and tap the calipers and master with a wooden handle to dislodge any air bubbles.
If that doesn't help then I would remove the master, rebuild it, and try again after bench bleeding.
Burning Brakes
Joined: Sep 2002
Posts: 1,179
Likes: 3
From: SF East Bay CA
It is likely air. Follow the correct bleeding sequence on the calipers. I would use a pressure bleeder as well. Using the old wife in the car hitting the pedal doesn't really work on these cars.. that's why I bought a pressure bleeder many yerars ago!
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
I've had the same problem with my 79. Having someone pump the breaks while I bled the system didn't get it. Out of frustration, I gave up and let the car sit overnight. The next day, I gravity bled all lines. Took a while but cured the problem. I agree that air must have been trapped some where and the normal pumping didn't push it out. Maybe sitting overnight allowed the air to better collect somewhere.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
The warning light is telling you there is air in the system. Letting it sit over night might help and gravity bleeding might be the way to go. Sometimes its stuborn. Watch carefully to see if you get air.
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Racer
Joined: Apr 2006
Posts: 340
Likes: 0
From: Warrensburg MO
If you pump the brakes, does the pedal get better? If so, you have air. If not, you must have a leak someplace; internal or external.
Was the pedal good before you changed the brakes?
Tommy
Was the pedal good before you changed the brakes?
Tommy
Last edited by tommyleea; Feb 20, 2008 at 12:39 PM. Reason: addition
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
are you sure that the rod that goes into the master cylinder is adjusted correctly? have some one take the top off the master cylinder and then push on the brakes gently........note when the first bubble pops up......if its not almost immediate then you need to lengthen the rod....you may also have air but i'm guessing that your push rod length needs adjustment. it should have about 1/8 -1/4" travel or so.
Instructor
Joined: Jun 2004
Posts: 182
Likes: 0
From: Sun Peaks British Columbia
I had exactly the same problem. (I know this is going to generate disagreement), BUT, I'll bet it's your vacuum Booster.
I changed: Rotors, pads, master cylinder, proportioning valve, & bled the living daylites out of the system, and it wasn't til I changed the
f-----g vacuum can, that pedal came up nice and high.
There! I've said it.
YV
I changed: Rotors, pads, master cylinder, proportioning valve, & bled the living daylites out of the system, and it wasn't til I changed the
f-----g vacuum can, that pedal came up nice and high.
There! I've said it.
YV
Instructor
Joined: Nov 2007
Posts: 183
Likes: 0
From: Corpus Christi TX
i had the same problem on my 80 i found the left rear caliper was bad at the pistons guess it was rebuilt poorly.... so i replaced it and put speed bleeders on all the calipers bled the system with a motive power brake bleeder from jegs which everyone recommends on this site and now its all good. now im waitin on uncle sam to for SS brake lines to firm them up the rest of the way and look into slotted and cross drilled rotors.
