78 Brake problems
Thread Starter
Pro
Joined: Jun 2011
Posts: 588
Likes: 41
From: Ohio
78 Brake problems
Brake pedal on my 78 SA goes way down almost to the floor. It will stop the car but not sure it will lock tires or not. The power booster seems ok since pedal goes down about 1/2 in and then is rock hard with engine off. Have blocked off master cyclinder ports and have hard pedal at the top. Have bled brakes and checked for leaks but have none. Also not losing any fluid out of reservoir. What am I missing??
Lonzoo
Forgot that I have decent pedal in garage but as soon as I back it out the pedal goes down and brake lite comes on..pump it again and back to normal..next stop sign routine repeats again and again and.well you get my drift.
Lonzoo
Forgot that I have decent pedal in garage but as soon as I back it out the pedal goes down and brake lite comes on..pump it again and back to normal..next stop sign routine repeats again and again and.well you get my drift.
Last edited by lonzoo; Aug 12, 2012 at 09:55 AM.
Racer
Joined: Sep 2007
Posts: 288
Likes: 1
Brake pedal on my 78 SA goes way down almost to the floor. It will stop the car but not sure it will lock tires or not. The power booster seems ok since pedal goes down about 1/2 in and then is rock hard with engine off. Have blocked off master cyclinder ports and have hard pedal at the top. Have bled brakes and checked for leaks but have none. Also not losing any fluid out of reservoir. What am I missing??
Lonzoo
Lonzoo
I could have written your post. I too am having the exact problem. I have asked the forum members here. The consensus is I still have air in the system.
What system did you use to bleed your brakes? Anything new? Did this just happen overnight?
I am still waiting to get my car back so I can take it to a professional to get it pressure bled.
I will be watching with great interest. I know some members will help you.
Good luck
Melting Slicks
Joined: Mar 2007
Posts: 2,100
Likes: 12
From: Frederick Maryland
In the '78 I used to own I had a similar problem. In my case it turned out to be a bad caliper seal...it wasn't leaking fluid but instead was sucking in air. Once that was diagnosed and taken care of I had no more problem.
Thread Starter
Pro
Joined: Jun 2011
Posts: 588
Likes: 41
From: Ohio
CGC.. yes it started rather suddenly. I used the 2 person method of RP.RD.FP.FD..of course doing the inside bleeders first on the rears.
Thanks RR..did not know that could happen. How did you find out it was doing that with no leak present?
thanks for the response and I will keep u posted CGC and besure to let me know if u find the cure before me.
Thanks RR..did not know that could happen. How did you find out it was doing that with no leak present?
thanks for the response and I will keep u posted CGC and besure to let me know if u find the cure before me.
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
Recently replace 2 calipers and master cylinder. After bleeding MC first then all 4 corners I had no resistance. Bled system two more time and no pedal. Turns out I introduce air at the MC and each time I bled the system I only move the air a little further through the lines. Eventually I gravity bled the brakes I now have the best brakes since I have owned the car.
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Instructor
Joined: May 2012
Posts: 103
Likes: 0
From: Warren MI
Recently replace 2 calipers and master cylinder. After bleeding MC first then all 4 corners I had no resistance. Bled system two more time and no pedal. Turns out I introduce air at the MC and each time I bled the system I only move the air a little further through the lines. Eventually I gravity bled the brakes I now have the best brakes since I have owned the car.
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
I don't think it was every time. Just when I replaced the master cylinder. At that point air was at the top of the lines and had to be pushed all of the way through the system. Since I started with the rear calipers that is probably the long way the air went.
The process was frustrating and I thought something else could have been wrong but luckily air was it.
Good Luck with yours
The process was frustrating and I thought something else could have been wrong but luckily air was it.
Good Luck with yours
Instructor
Joined: May 2012
Posts: 103
Likes: 0
From: Warren MI
I don't think it was every time. Just when I replaced the master cylinder. At that point air was at the top of the lines and had to be pushed all of the way through the system. Since I started with the rear calipers that is probably the long way the air went.
The process was frustrating and I thought something else could have been wrong but luckily air was it.
Good Luck with yours
The process was frustrating and I thought something else could have been wrong but luckily air was it.
Good Luck with yours
Thread Starter
Pro
Joined: Jun 2011
Posts: 588
Likes: 41
From: Ohio
Think my fight is over. Today I put on new MC. Bled MC on bench then left fittings loose and with wife gently pushing pedal down let fluid run out before tightening fittings. Since bleeding 3 times with 2person method with no luck I bought a vacuum pump and decided to pump out all old fluid as i bled each caliper. The old fluid looked watery and had color of 10,000 mile motor oil. Have good pedal now.
thanks for all the help guys, Lonzoo
thanks for all the help guys, Lonzoo
Racer
Joined: Sep 2007
Posts: 288
Likes: 1
[QUOTE=lonzoo;1581539683] Have blocked off master cyclinder ports and have hard pedal at the top.
lonzoo
Glad to hear you fixed your brakes.
This may seem like a silly question. Do you think it was the MC or rebleeding the brakes? The reason I ask is you had hard pedal with ports blocked.
If MC then I will buy another and try again.
lonzoo
Glad to hear you fixed your brakes.
This may seem like a silly question. Do you think it was the MC or rebleeding the brakes? The reason I ask is you had hard pedal with ports blocked.
If MC then I will buy another and try again.
Thread Starter
Pro
Joined: Jun 2011
Posts: 588
Likes: 41
From: Ohio
CGC
I really think the main problem was the nasty dirty fluid which had the MC really gooked up. I decided to go ahead and put new MC on after I saw how ugly it was inside after removing old fluid. When I went to my local Autozone they did not have a new one but had a rebuilt one for $17.99 so I took it. I am sure the bad fluid had bad effects on all the operational parts of the brake system. For 17.99 I would give the MC a shot.
Thanks, Lonzoo
I really think the main problem was the nasty dirty fluid which had the MC really gooked up. I decided to go ahead and put new MC on after I saw how ugly it was inside after removing old fluid. When I went to my local Autozone they did not have a new one but had a rebuilt one for $17.99 so I took it. I am sure the bad fluid had bad effects on all the operational parts of the brake system. For 17.99 I would give the MC a shot.
Thanks, Lonzoo