Brake Distribution / Proportion Valve

[MikeStang 247]

Ok I'm Sure everyone knows what I'm talking about...The big Brass Block under the hood that your lines go into That's the one.

 

So here is my question

 

Since I upgraded the brakes on my 69 and My Prop valve or Combination valve as you want to call it is in need of a rebuild do I even really need it... Here's why I'm wondering.

 

I have an adjustable valve with the little bullet shaped buffer for the rear brakes so the fluid travel out of the MC will go right to the regulated valve that I can adjust and will be softened by the little buffer for the rear.

 

The front lines simply go from the MC into the top of the block and then back out the the front brakes....

I have no need or intention of using the little brake idiot light since I have aftermarket gages.

 

So this being said can I just use a Brass T-Block on the front and go from MC and split it to each side Via the "T"

 

and for the rear just go right out of the MC down to the Adjustable Prop Valve mounted in the back of the car.

 

I mean does the Combo valve do any regulation on the front because its an In and an Out...

I dont wanna waste 50 bucks to get the stupid rebuild kit when I dont need 1/2 of the crap in there since I dont need to rebuild the stock little bullet shaped thing since I am using an aftermarket unit.

[Rsanter 152]

That block is only a way for the car to compair pressures between front and back so if one end fails it can trip a little light on the dash.

Look at some of the race car supply places or even the early mustangs or other fords

 

Front

Come out of the MC to a 3 way fitting to the two front brakes

 

Rear

Come out of the MC to the prop valve and then to the line to the rear

 

You are done

[MikeStang 247]

Exactly what I was hoping.. saved me 50.00 and a 2 day wait on a rebuild kit.. u da man.

[stangs-R-me 121]

The other thing the '68-69 block did was BYPASS the rear prop valve IF the spool shifts forward due to a front brake system failure ... giving you full system pressure to the rear brakes when they are all you've got.

 

I'm pretty sure the '70-up block with the integral prop valve does this same thing but internally.

 

Just something to think about.

 

 

When I rebuilt my brake system, I put my adjustable K-H prop valve in SERIES with the Ford one (so I would still have the by-pass function) and find that I have real good bias adjustment set up like this.

 

Hard to really see the "in series" plumbing in my pic, but you get the idea.

 

Doug

[MikeStang 247]

Ok So last night I plugged off all the holes in the distribution block except the 3 for the Front brakes and I also removed the little slider piece inside the valve and hooked up the front brakes.

Then I just went right from MC to the rear line into adj Prop valve in rear...Finally got it leak free...the Double flare I had a fellow do leaked like a sieve so I cut it and single flared it and its now leak free lol.

 

I do have this one question however.

Now that I have removed the little internal piece and plugged all the un-used holes in the Main Prop Valve does it matter that there is all of that empty space in the valve that is now filled with fluid or do I need to put a small T- and split to the 2 front lines.

Basically I'm Wondering if having all of that extra volume of fluid in the Prop valve that is no longer occupied by the little slider insert will effect anything?

 

The pedal feels weird but I think I need to adjust the Master Cyl push rod but I have to see because I have an adjustable rod that came with the booster when I bought it and a rod that came with the Granada Brake upgrade kit LOL...So I dont know..It looks nice with the big valve and all the SS lines tho lol

[Rsanter 152]

In theory what you did should be just fine.

The problem is that you have a large cavity that has the potential to hold an air pocket or bubble. Also there is the remote chance over time that you could have some moisture from the system try to accumulate in there.

What did you plug the hole for the warning light with? A metal plug or the original plastic switch?

It needs to be a metal plug or bolt with a copper washer under the head.

 

If it was me I would have prefered to leave the slider, plug all holes associated with the rear brakes and just leave it at that.

 

Bob

[MikeStang 247]

I used all Copper Inverted Flare Plugs..I did it right.

Only reason I took Slider out was because it didn't have the oring's or anything on it and didn't know if it might cause a flow disruption problem in some way.

I didn't think about the Air Pocket Issue.

 

Now let me ask this.

The Original Master Cyl had different line diameter holes and looks a bit different than the one that came with the Granada Brake Kit.

I bought a Stock Booster for a 69 Stang and it came with a Master Cyl Push Rod so I used that one instead of the one that came with the Granada kit.

The Original design one has just a tip that screws in and out, the Granada pushrod is a more of a 2 piece deal with the split in the middle to screw it in and out,,,, Guess I need to compare the length of the two and see whats up.

 

I know when I put it in the first time I remembered that the tip was screwed out and the pedal was WAY high, so pulled it out and screwed it all the way in and reinstalled and pedal level was about right, but it doesn't feel right when you start pushing it down there is resistance until you get 3/4 of the way down and then it feels like it Cams over really odd.

 

If I recall arent you supposed to measure the length by inserting the push rod and then laying a straight edge across the Booster and measure down to the tip of the rod and adjust the rod till your in the .95 to .97 range?

 

When I put the master on the booster it slid on but then I had to tighten the bolts down to get it to sit flush so im assuming it was a little too long which means I need to try the other rod since I screwed that one all the way down already

[Rsanter 152]

If you are not flowing fluid through anything but the front part of the dist block then the O rings are irreverent in that block. If it was me I would put the rod back in and leave the O rings out and say so be it.

 

I installed a booster from tuff stuff that is similar to the boss429 booster. Brand new was cheaper than a rebuild of the original and I got it in Crome.

I needed this one because I installed a willwood master cylinder which is longer than the stock one.

Note that the master cylinder has a part that sticks out from the mounting flange. I measured the depth of this boss. Then I measured from the flat of the boss to the bottom of the hole for the rod in the MC. Subtract one from the other and you have the depth of the hole from the mounting flange.

Then take a straight edge across the booster and measure lenth of the rod. You want those dimensions to be as close as possible with the rod a smidge shorter

 

Bob