I just converted my 1963 impala ss drums to a front disc and rear drum. I'm having trouble figuring out the proportioning valve. Mainly, which line connects where. the brass valve has two lines at the top connecting to the mater cylinder. then two 3/16 lines (not sure where these will connect to) then one last one on the back end of the valve (larger opening, not sure of the gauge)

any ideas where the two 3/16 lines go and the back end of the valve connects too?

all help is appreciated...

OK 1st thing did you change the single master cylinder to a dual master cylinder? IF so I will look at my cars and let you know how they are hooked up.

Yes I now have the dual master cylinder...

It goes into the front line on the master cylinder that feeds the rear brakes. Is it an aftermarket adjustable or a solid block off of another year vehicle?

Big Dave

it's a solid block off of another year....not sure what year though. I got the disc conversion kit in an ebay auction. good product but no tech support to go with it...

id assume the 2 3/16 ports go to the brakes front and back. im not 100% But for some reason i remember hearing that usually the front port is for the rear brakes and the rear for the front brakes.. no wait.. thats for the master cylinders... right??
the big one you are reffering to(on the back). maybe for a pressure switch of some sort incase you loose brake pressure.. maybe its supposed to have a plug in it..

YouTube - Installing High Performance Brakes on a Custom Car : How to Install a Proportioning Valve to a Master Cylinder

well aint that some ****. is that the style you have. i didnt watch the whole thing so i dont know how far it goes.

that IS the exact set up I have....any thoughts as to where the brake lines go once the prop valve is connected TO the master cylinder. that the main snag I'm running into...and thanks again for the help so far...

all i can think of is one goes to the front(probably a T or something) and one to the rear.
and that T would be to just make 2 out of one.
as to where they are run physically.. no clue. but you would probably be safe to put them somwhere that they wont be exposed to too much heat or anything that may rub or crush them.
i think stock was along the upper side of the Xframe all they way to that plate that goes across the rear frame rails.
and i think the front is down to the driverside frame rail to a T then along the crossmemeber to the other side.
hope that helps a bit more.

With all of this talk of "T's" I have to ask. Do you have a new dual reservoir master cylinder, or the stock single cylinder master brake cylinder. You should have converted over to an isolated dual brake system with separate front brake lines and rear brake lines (which is the circuit that contains the proportioning valve). You will need a residual valve for the front brakes if you are housing discs, and proportioning valve for the back with a manifold beneath the dual cylinder that has a safety switch that sees an imbalance in the event of a failure that causes brake light to warn you of the failure.

Big Dave

so dave. just to clarify for me here. after the dual master cylinder (which he stated he does have) 2 lines go the the proportioning valve. after that 2 lines come out.
from that point one line goes to the front and one to the back. those two lines that go front and back need to be split from one into two so that they can feed both left and right sides of the front and rear.. thats where them Ts would come into play.

but what is this residual valve you speak of?? what is it for?

Zack,
Look at the master cyl. and see if there is a residual valve in one of the 2 outlets. There should be one in the front outlet. The outlet that has the valve is the one that goes to the rear drum brakes. This is important as the valve holds a RESIDUAL pressure in the line for the drum brakes, there are no valves in the master cyl. on disc brake systems.

hey big iron. is that just a check valve?? or does it do more?

socapots,
The residual pressure valve is not a check valve as pressure goes thou the valve in both directions. A check valve would only allow pressure in one direction. If you did not remove the residual valve when you install disc brakes the residual pressure would keep the the pads applied ( ever so slightly ), which would cause the disc to get hot and premature wear of the pads.
Bob C

The stock three outlet port proportioning valve has a built in 10 psi residual valve for the rear drums. That is the principle reason for deep sixing the stock part in favor of an adjustable one when going to rear disc brakes. On the stock valve the front two holes feed the front disc brakes and the single rear port feeds the drums.

Big Dave

ahhhhh.. i get it now. so it basically does what it says. lol. keeps some pressure in the line. but not all of it.
makes sense. i was wonderin about that after thinkn a check would be pointless as it would hold the brakes on to whatever extent they were applied lol.