low brake pedal?
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Joined: Mar 2009
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low brake pedal?
74 c3 with stock engine-for now. Trying to bleed the power brakes. Have replaced 3 of 4 calipers for leaking and new master cylinder. Pressure bleed, pumped by foot, vac bleed, pressure bleed. 3 GALLONS later i still have a poor pedal-any tricks out there. Could the pads be compressing or the calipers moveing? Have bleed all 6 bleeders- 2 front and 2 rear and also master cylinder.
Last edited by kkperformance; Apr 22, 2012 at 09:46 AM. Reason: mistake
Burning Brakes
Joined: Jun 2010
Posts: 1,165
Likes: 93
From: Bellmore NY
Might as well do that last caliper to rule it out, but perhaps your rubber hoses are in bad shape.
I just changed both rear calipers and corresponding rubber and steel lines. Gravity bled and then bled with neighbor's foot. Ive got good brakes for the first time.
I just changed both rear calipers and corresponding rubber and steel lines. Gravity bled and then bled with neighbor's foot. Ive got good brakes for the first time.
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Joined: Apr 2009
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Hiya,
First: Replace that last caliper. It's been said to replace it in just about every response on this thread so it's obviously important.
Second: The typical parts stores that sell us a master cylinder don't realize that our master cylinders came with a deep hole and a shallow hole for the push rod that resides between the master cylinder and the brake booster. I would compare the depth of the hole between your new master cylinder and the one that you removed. If they are the same, that still may not be the answer if your brakes were performing poor to begin with. The PO if there is a PO could have put the wrong master cylinder on and just suffered through terrible brakes. I went through this same BS and when I got it sorted out I had brakes that were respectable.
Good Luck!
First: Replace that last caliper. It's been said to replace it in just about every response on this thread so it's obviously important.
Second: The typical parts stores that sell us a master cylinder don't realize that our master cylinders came with a deep hole and a shallow hole for the push rod that resides between the master cylinder and the brake booster. I would compare the depth of the hole between your new master cylinder and the one that you removed. If they are the same, that still may not be the answer if your brakes were performing poor to begin with. The PO if there is a PO could have put the wrong master cylinder on and just suffered through terrible brakes. I went through this same BS and when I got it sorted out I had brakes that were respectable.
Good Luck!
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
Do you get air out of the system when you bleed it? Do you get fluid out of each bleeder? Does the pedal ever pump up when you bleed it? Are bleeding with the engine running or off?
What I'm looking for is 1) the fluid is getting to all parts of the calipers, 2) the master is working properly (even though it's new, doesn't mean it's good) and if the brakes are bleed with the engine running, it's difficult to tell when you're actually moving the master cylinder making it highly likely you're sucking air as well as pushing brake fluid.
And finally, I don't mean to offend but maybe your bleeding procedure is wrong?
When these systems are working properly they're actually pretty good. A good firm pedal and plenty of stopping power for a stockish car.
What I'm looking for is 1) the fluid is getting to all parts of the calipers, 2) the master is working properly (even though it's new, doesn't mean it's good) and if the brakes are bleed with the engine running, it's difficult to tell when you're actually moving the master cylinder making it highly likely you're sucking air as well as pushing brake fluid.
And finally, I don't mean to offend but maybe your bleeding procedure is wrong?
When these systems are working properly they're actually pretty good. A good firm pedal and plenty of stopping power for a stockish car.
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
Sounds normal with vacuum boost.
Last edited by Paul L; Apr 23, 2012 at 07:17 PM.
Melting Slicks
Joined: Mar 2007
Posts: 2,520
Likes: 11
From: Hinckley OH
I just went through this with my '74. When I was bleeding my brakes and "testing" the pedal, it seemed like there wasn't enough pedal. But when I drive it normally, the car will stop with the pedal at about the height of the gas pedal. That's about where it is on my '76 and in fact on my brand new 2012 Subaru Legacy. Even on the Subaru if I push the pedal hard with the engine running, I can push it almost to the floor. I think we all look for a good hard pedal, but it just doesn't work that way with power brakes. Hopefully, you have a big space where you can test it without danger of hitting anything if your brakes aren't working. I have the space to test drive it.
Instructor
Joined: Jan 2012
Posts: 201
Likes: 0
From: some hole in the ground town- camp verde:) arizona
Hiya,
First: Replace that last caliper. It's been said to replace it in just about every response on this thread so it's obviously important.
Second: The typical parts stores that sell us a master cylinder don't realize that our master cylinders came with a deep hole and a shallow hole for the push rod that resides between the master cylinder and the brake booster. I would compare the depth of the hole between your new master cylinder and the one that you removed. If they are the same, that still may not be the answer if your brakes were performing poor to begin with. The PO if there is a PO could have put the wrong master cylinder on and just suffered through terrible brakes. I went through this same BS and when I got it sorted out I had brakes that were respectable.
Good Luck!
First: Replace that last caliper. It's been said to replace it in just about every response on this thread so it's obviously important.
Second: The typical parts stores that sell us a master cylinder don't realize that our master cylinders came with a deep hole and a shallow hole for the push rod that resides between the master cylinder and the brake booster. I would compare the depth of the hole between your new master cylinder and the one that you removed. If they are the same, that still may not be the answer if your brakes were performing poor to begin with. The PO if there is a PO could have put the wrong master cylinder on and just suffered through terrible brakes. I went through this same BS and when I got it sorted out I had brakes that were respectable.
Good Luck!
i had this same problem with mine
Thread Starter
Advanced
Joined: Mar 2009
Posts: 90
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pedal goes 1/2 way before i get anything, feels like its 1/2 off floor when i push firm to stop. NO air when bleeding. correct procedure and clean fluid at calipers, I will replace the last caliper and rebleed. the pedal NEVER pumps up when bleeding, or i mean if you pump it it does not get better. Just wanting to make sure there is a problem as this is my first c3.
