dennisonwj

New to the Forum, Hello All. I am working on a 1969 Barracuda that I recently purchased. I DO NOT have the build sheet and need some ideas on the direction I need to go on a brake repair. The vehicle is a 340 small block with front discs and rear drums. Here are the questions. Note : Please forgive me, I have done brake jobs but I am lacking information on the vehicle specifications here.

1) How would I know if the front disk brakes were factory installed or after-market? One of the pictures below shows the caliper and you can see "A71312" on the passenger side one.

2) Is the picture below a proportioning valve or a distribution block? I am concerned someone just threw on front disc brakes and did not install a proportioning valve nor install the correct master cylinder.

3) The master cylinder is manual and there is a "20872" stamped in the rubber seal gasket and made in "U.S.A." BUT both chambers are the same size/volume like it is for a 4 wheel drum car. Again, I am concerned someone bush-leagued the brakes and did not install a proportioning valve the correct MC.

4) The vehicle does not seem to lock up the rear wheels when braking and without a proportioning valve that would happen, right?

- Will

RacerHog

As far as I know... No Disc factory installed in 69...
Not sure the bleeder screw should be pointing down... Leads me to thinks is some type of aftermartket..
Yes that is a proportioning valve...

dennisonwj

On another forum, people told me it was NOT a proportioning valve, but a distribution block instead.
That is not the bleeder screw but where the hard line attaches from the soft rubber line, the bleeder is on the other side of the stem coming out the top, so you have to remove the wheels to bleed the brakes, because the bleeders sit behind the wheels in front of the dust covers.

RacerHog

After looking at one of my older sale brochures, I have found that Front Disc brakes where and Option when ordering. I was thinking it was a dealer installed item. But i was wrong on that.

As for the Block.. I know it as a proportioning valve. Why are others calling it a Distribution Block? No Moving Parts inside?

dennisonwj

I think the Distribution Block is just an avenue to hook up brake lines and route fluid, whereas a Proportioning Valve has items inside to reduce the pressure to the rear drums to "EVEN" out the brake pressure to all 4 wheels when you have disc brakes in the front and drums in the back. Several folks now have confirmed the picture I sent is ONLY a DB not a PV. This http://www.doctordiff.com/1-piece-pr...ing-valve.html is a REAL PV so they added PV capabilities to a DB, so it is an inch taller roughly than a stock DB.

RacerHog

Distribution would be for all drum brakes...
Combination Valve would be to control Disc to Drum...
So I would say that you have a Combination Valve in the photo..

Does your car have one of these by any chance?
https://www.classicindustries.com/pr...ts/md2274.html

dennisonwj

A combination valve and a proportioning valve my research shows are the same thing.
This is a combination/proportioning valve : https://www.classicindustries.com/pr...ts/md2268.html
This is a distribution block (looks like what is in car) : https://www.classicindustries.com/pr...ts/md2267.html
This is attached to the rear axle to distribute the brake lines. https://www.classicindustries.com/pr...ts/mn1156.html

No I do not have one one of those Texas shaped valves in the brake line from front to rear, which means my car was probably a 4 wheel drum and after delivery it was made it a K-H front disc configuration but the person that did it did not add a combination/proportioning valve, nor swapped out the master cylinder to one with a larger rear reservoir to handle the extra PSI needed for the front brakes as well as fluid drop from wear on the pads and run out.

ZEN357

I get yourself a good set of PowerStop Brake Calipers, Rotors, and pads for the front and convert the back as well to PowerStop Disc Brakes.

RacerHog

IF the master cylinder was not changed out and it has the wrong block as you suspect.... Then the system would have the wrong residual valving at least for the front caliper... That will give you a lack of pressure and a spongy long traveled pedal.

dennisonwj

I may go to those later, want to get the car safe enough for the summer. Thanks.

dennisonwj

I think that is exactly how it feels, it will stop, but you need lots of room in front of you. I am going to spring and just get the device I KNOW is a proportioning/combination valve. Very little money to spend to ensure my wife's safety. This is her car really.

RacerHog

Keep us posted on what works and what you find out...

dennisonwj

I will. Thanks to all of you for your guidance and help. I am ordering parts tonight.

TVLynn

bleeder screw should be on top so the air can be bleed out