1968 brake problem
Thread Starter
Heel & Toe
Joined: Jun 2006
Posts: 24
Likes: 3
From: Ulster PA
1968 brake problem
I am looking for help on solving a problem with the bleeding the brakes on my 1968. I am using a Motive power bleeder, calipers have been rebuilt with SS liner's and VPB piston with "O" rings, replaced the master cylinder, however with 10lbs. pressure the fluid just barely comes out of the bleeders. Any help would be greatly appreciated.
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Thread Starter
Heel & Toe
Joined: Jun 2006
Posts: 24
Likes: 3
From: Ulster PA
Is there anyway to check the proportioning valve? I suspect this is where the problem is. I will try removing the bleeder's one at a time.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
How old are your flexible hoses to the calipers? Those can look ok but be swelled almost closed on the inside. You could try removing the hose from one of the hard lines and see what flow you get.
Thread Starter
Heel & Toe
Joined: Jun 2006
Posts: 24
Likes: 3
From: Ulster PA
I have no idea how old they are. I will try your suggestion on the front. I am having the same issue on all four wheel,s.
Thread Starter
Heel & Toe
Joined: Jun 2006
Posts: 24
Likes: 3
From: Ulster PA
I was reading about this in a Chilton's manual and it states that a brake warning light on the instrument panel should come on. Is this the same light as the emergency brake light, because that is the only brake light that I have?
Melting Slicks
Joined: Jun 2009
Posts: 2,343
Likes: 4
From: Anderson SC
Hi Mike!
I just went and checked my car and there's no way to be sure exactly "what" it is by looking at it.
It's there, and it has a wire attached to it for the light. Ecklers however, lists it as a "Proportioning Valve" at part number 48514. A different one is listed for 1969 (48515) and then 3 more for 70-73 , 74-77, and 78-82. They also have a chrome "replacement" for 74-82 at ony $79.
Are you sure it's not a true proportioning valve? Is the '69 one "real"? If not when did they get "real"? And lastly if you had a '68 would upgrading this critter to a real proportioning valve make a notable difference in brake performance. Do they all have the light switch built in?
-W
I just went and checked my car and there's no way to be sure exactly "what" it is by looking at it.
It's there, and it has a wire attached to it for the light. Ecklers however, lists it as a "Proportioning Valve" at part number 48514. A different one is listed for 1969 (48515) and then 3 more for 70-73 , 74-77, and 78-82. They also have a chrome "replacement" for 74-82 at ony $79.
Are you sure it's not a true proportioning valve? Is the '69 one "real"? If not when did they get "real"? And lastly if you had a '68 would upgrading this critter to a real proportioning valve make a notable difference in brake performance. Do they all have the light switch built in?
-W
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Yes, it shares the same light. It's easy enough to know if the light works, but difficult to know if the switch inside the valve works or not. I have heard of cases where the valve has been activated but that the switch is not working.
This may be contributing to your bleeding problems but check out all the normal culprits first.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Originally Posted by Clams Canino;
Are you sure it's not a true proportioning valve? Is the '69 one "real"? If not when did they get "real"? And lastly if you had a '68 would upgrading this critter to a real proportioning valve make a notable difference in brake performance. Do they all have the light switch built in?
-W
Melting Slicks
Joined: Jun 2009
Posts: 2,343
Likes: 4
From: Anderson SC
Yes... I read the break sticky thread in the C3 tech forum and now feel I have a good education on what that foolish thingie does and does not do.
My LR caliper is currenty bad - so I can assure you that mine works, and the light comes on, and then the light goes back off... so I know that the pistons are at least trying to re-center.
I'll note that by the time you push the pedal down far enough for the idiot light to come on - you should already have gotten clues that something is wrong with the brakes.
My LR caliper is currenty bad - so I can assure you that mine works, and the light comes on, and then the light goes back off... so I know that the pistons are at least trying to re-center.
I'll note that by the time you push the pedal down far enough for the idiot light to come on - you should already have gotten clues that something is wrong with the brakes.