74' Brake Fade - Help!!!

[igasper10]

I have all new calipers & lines on my 74'. They've been bled in the correct sequence, but the pedal still goes almost to the floor! I read someone's reply to someone else who was having this problem, and he said to check the power brake booster. I'm not familiar with that term... where is this in relation to the master cylinder??? A list of things to check would be great from anyone that's had these problems before. It sounds like a lot have...

Ian -

 

[Bob Chadwick]

The power brake booster is the big cannister that the master cylinder attaches to.

 

[clar2001]

Sounds like air if you have all new calipors, why not put a new master cylinder on too, I have a complete new braking system had to bleed it three times to get all the air out , so I would have full peddle .
Did this problem only occur after new install, If yes most likely air ,if it was allready a problem then maby rotor run out . or master cylinder...
Be shure to bleed your calipors on both sides mine have four bleeders on each one will easly hold a pocket of air and soften up your brakes.............Good Luck

 

[Bob Chadwick]

Sounds like air if you have all new calipors, why not put a new master cylinder on too, I have a complete new braking system had to bleed it three times to get all the air out , so I would have full peddle .
Did this problem only occur after new install, If yes most likely air ,if it was allready a problem then maby rotor run out . or master cylinder...
Be shure to bleed your calipors on both sides mine have four bleeders on each one will easly hold a pocket of air and soften up your brakes.............Good Luck

I agree. Master cylinder took less than an hour. At the same time replace the four rubber hoses at the brake calipers.

Firestone will bleed the system with their machine for $60. Guess what I did to avaoid the hassle of pulling all four wheels off. If I had a lift it would have been another matter.

 

[clar2001]

I had one of those stupid rubber lines in the back go bad, so after you aplied brake it would not realise pressure on that wheel thought I had a bad bearing,car draged and that wheel got hot allready had new brake bads and callipors.$10 fix once I fiqured it out,but that took three weeks and new bearings ops,
So my thought are,if your going to do brakes do it all . it doesen't pay to save bite the bullet spend the money and stop safely...

 

[Fast Ed]

I have the same problem with my 76 and everything except the proportioning valve is new. It has been properly blead several times and not solved yet. Sorry I cannot help but when I find it I'll let you know
Ed

 

[cruisin-davey-g]

I have all new calipers & lines on my 74'. They've been bled in the correct sequence, but the pedal still goes almost to the floor! I read someone's reply to someone else who was having this problem, and he said to check the power brake booster. I'm not familiar with that term... where is this in relation to the master cylinder??? A list of things to check would be great from anyone that's had these problems before. It sounds like a lot have...

Ian -

Ian: Sounds as if you still got air somewhere in the system. The only real way to properly bleed a 4 wheel disc brake system is to "pressure bleed" to get all of the air out. It is not your brake booster. If your brake booster were not working, you peddle would be hard. If your power brake were to have a leak, your brake system would be locked up (like pushing & holding the brake peddle down hard while trying to drive) this would definately burn up your brakes. I've had this happen & I was driving at about 40 miles per hour & by the time I got the car to stop correctly, all of the calipers were smoking. Not a pretty site.

Dave:

 

[Eric]

Gotta go with the crowd on this one. Same thing happened when I replaced the calipers, lines, and master cylinder on the 71. Bled the whole system, went to back out of the garage and the pedal went to the floor as I drove over one of Kelly's potted plants. Pulled back in the garage (very slowly:L) and bled the whole thing two more times and that did the trick.

 

[igasper10]

FORGOT TO MENTION...

Sorry guys... :duh I forgot to mention I replaced the master cylinder as well. It wouldn't make much sense to replace all calipers, lines, brake pads, and not replace the heart of the brake system! I'll try getting them pressure bled after I take care of my gas tank issue. Thanx for all your help!!!

Ian -

 

[cruisin-davey-g]

Re: FORGOT TO MENTION...

Sorry guys... :duh I forgot to mention I replaced the master cylinder as well. It wouldn't make much sense to replace all calipers, lines, brake pads, and not replace the heart of the brake system! I'll try getting them pressure bled after I take care of my gas tank issue. Thanx for all your help!!!

Ian -

Ian: Hey, keep me posted & let me know what you find out

Thanx Dave:

 

[Steve Grodin]

Re: FORGOT TO MENTION...

Sorry guys... :duh I forgot to mention I replaced the master cylinder as well. It wouldn't make much sense to replace all calipers, lines, brake pads, and not replace the heart of the brake system! I'll try getting them pressure bled after I take care of my gas tank issue. Thanx for all your help!!!

Ian -

Did you also bench bleed the master cylinder?