More brake problems
Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,818
Likes: 13
From: ar
More brake problems
I know this has been covered before, Here is the question? I am working on sons 73 and we have been chasing the brakes for a few years. I can't get a good solid pedal.
We have put on 1 new booster and 3 master cylinders. The calipers are stainless and don't leak and I don't think they are sucking air. The car will stop ok but always seems to have mushy pedal.
I am wondering if the porportioning valve could be a problem or maybe the rod from the pedal isn't adjusted out far enough (we put in clutch and brake pedals to switch from auto to standard)? Any help would be great. Thanks SSS
We have put on 1 new booster and 3 master cylinders. The calipers are stainless and don't leak and I don't think they are sucking air. The car will stop ok but always seems to have mushy pedal.
I am wondering if the porportioning valve could be a problem or maybe the rod from the pedal isn't adjusted out far enough (we put in clutch and brake pedals to switch from auto to standard)? Any help would be great. Thanks SSS
Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,818
Likes: 13
From: ar
mushy brakes
Yep, we used steel braided lines , I thought we had a soft rubber line. Been bleeding these things for years and finally broke down and bought a motive products pressure bleeder, thought that would help, but no luck. Any more ideas? SSS
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Bleeding the lines/calipers only helps if there is air trapped inside. When you bleed them, are you getting any air out of them? I attach a clear plastic hose, approx 1/8", to the bleeder until I see a stream of fluid without the tiny air bubbles.
In my opinion, new cars today have a slighly different feel in regards to the brake pedal effort.
In my opinion, new cars today have a slighly different feel in regards to the brake pedal effort.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Try again, do the pressure bleed...don't know if yours is air powered or do you pump the pressure by hand, but use a low pressure, and tap on the caliper with a hammer to dislodge any air bubbles. When you get a nice steady flow, remove the pressure bleeder, then open the bleeder and let it flow by gravity, again tapping with a hammer. Do that for each wheel.
Don't forget to check your MC for fluid level.
Did that to mine and have a rock solid pedal, though I used a pressure bleeder that I made and 5 lbs of air.
Don't forget to check your MC for fluid level.
Did that to mine and have a rock solid pedal, though I used a pressure bleeder that I made and 5 lbs of air.
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Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,818
Likes: 13
From: ar
Mushy brakes problem
Thanks for the suggestions, I have run 4 cans through and used the clear lines and we think we have all the air out. I even gave up and took it to the guys at the shop that do all my normal brake and tie srevice and they are stumped.
I think we have some kind of strange problem in lines or porportion valve or something that doesn't occur normally.
Thanks for the suggestions SSS
I think we have some kind of strange problem in lines or porportion valve or something that doesn't occur normally.
Thanks for the suggestions SSS
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
I'm a big believer is getting rid of the proportioning/light switch. You can totally remove it or modify the block so it actually is just a dummy and the 2 systems/front and back are totally seperate.
You do not need a proportioning valve with our cars.
You do not need a proportioning valve with our cars.
Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,818
Likes: 13
From: ar
porportioning valve
Hey Norval, I agree, I have been running a dual master cylinder with disc on my 63 for years and a divided system with no porportioning valve and have no trouble and it has good balance. I was just trying to make the stock system work, but I am thinking about pulling the valve and give that a try. They say that a porportioning valve can cause funny thigs to happen.
Thanks SSS
Thanks SSS
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by norvalwilhelm
I'm a big believer is getting rid of the proportioning/light switch. You can totally remove it or modify the block so it actually is just a dummy and the 2 systems/front and back are totally seperate.
You do not need a proportioning valve with our cars.
You do not need a proportioning valve with our cars.
Safety Car
Joined: Oct 2004
Posts: 3,920
Likes: 731
From: Youngstown Ohio
Originally Posted by silverslashstreak
I didn't know what pressure to use.... I just pumped it to 10lbs. I will try it at a lower pressure and maybe do a little tapping.
Racer
Joined: Jan 2005
Posts: 365
Likes: 1
From: Glenview IL
Originally Posted by 45ACP
Don't forget that there are TWO bleeder screws on each corner out back. Folks have been known to overlook/forget that and get very frustrated with the results.
~Rich
Instructor
Joined: Sep 2003
Posts: 158
Likes: 0
From: 29 Palms CA
Ahh, brakes, my favorite. Just finally got a solid pedal on my 73. Did you bench bleed the new master cylinder first?? I have ran about 6 quarts of brake fluid through mine using one of those hand pump pressure bleeders. After months of frustration and sore hands, I was finally able to get good pedal this past week. Was starting to worry about the prop. valve myself. Air is a bi*** to get out! Good luck!
Burning Brakes
Joined: Nov 2005
Posts: 1,143
Likes: 0
From: Leander Texas
pressure bleeding
My pressure bleeder is a 25yr old Red Head. When I rebuilt the calipers on my '78 my wife got the great job of pumping until it was hard. I just use the time honored tradition of break bleeding passed onto me by my fore fathers. She just pumps the pedal until it gets hard, and I crack each bleeder open in the standard bleeding procedure.