Adjustable Brake Proportioning Valve
Thread Starter
Racer
Joined: Oct 2004
Posts: 379
Likes: 0
From: Thief River Falls Minnesota
Adjustable Brake Proportioning Valve
When putting in an adjustable proportioning valve, do you keep the old proportioning valve and just put the adjustable one after it, or can you put in a Y or a T block to the fronts off the front port on the master cylinder, and plumb the adjustable valve off the rear port going to the back? I'm wondering because the stock valve is off the car now and I was just wondering if I need it with the adjustable? As always thanks in advance. 
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Why do you need a proportioning valve at all?? The thing you call a proportioning valve is little more then a light switch. It is not a proportioning valve. You have different size caliper piston and that take care of proportioning.
If anything I feel our rear brakes are not strong enough. It is just a toy you are adding for something to play with???
If anything I feel our rear brakes are not strong enough. It is just a toy you are adding for something to play with???
Melting Slicks
Joined: Nov 2003
Posts: 2,362
Likes: 1
From: San Antonio TX
Just remember though every spin of the tire is a $1.oo bill floating off in the air. lol. And depending on what your tires cost it might be more. Kinda hits home when you think about it lol. 
lol. And depending on what your tires cost it might be more. Kinda hits home when you think about it lol.
Melting Slicks
Joined: Jul 2002
Posts: 3,000
Likes: 22
From: Boulder Creek California
So we should save money and go slower? 
Does our master cylinder have the same size 'piston' for front and rear? Anyhow yes we're probably fine for the street (and only the street) without a proportioning valve.
Does our master cylinder have the same size 'piston' for front and rear? Anyhow yes we're probably fine for the street (and only the street) without a proportioning valve.
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Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Originally Posted by 76custompaint
When putting in an adjustable proportioning valve, do you keep the old proportioning valve and just put the adjustable one after it, or can you put in a Y or a T block to the fronts off the front port on the master cylinder, and plumb the adjustable valve off the rear port going to the back? I'm wondering because the stock valve is off the car now and I was just wondering if I need it with the adjustable? As always thanks in advance.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Originally Posted by Duke94
It depends on what year Vette you have. From 68' thru about 73' there was no proportioning valve so you can install it DOWNSTREAM of the differential valve (the one with the switch mounted on top of the frame). If you have a later model that does have the proportioning valve, you need to render it non functional (search this site for how) then again install the adjustable unit DOWNSTREAM. Start out with the adjustable unit at it's minimun setting (least rear brake) and keep make adjustable a high decel stop. Adjust the valve one turn at a time until the rears just lock before the fronts, then back off about one turn. As you know, the fronts should always lock before the rears. Without getting to technical, if you install the second valve in series with the stock proportioning valve, the rear brake pressure will be reduced significantly more than either one by itself.
the front brakes should lock up first. If not use a prop valve in the rear line. If you want to do burnouts to heat the meats use a line lock.
