Do I need another proportioning valve
Thread Starter
2nd Gear
Joined: Apr 2017
Posts: 2
Likes: 0
Do I need another proportioning valve
I have a 73 and am replacing the master cylinder with a wilwood master. Can I just install it with the OE proportioning valve or do I need to get a new tandem adjustable proportioning valve? Thanks
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
You're original is a pressure differential switch and not a proportioning valve. The aftermarket unit you mention sounds like an actual proportioning valve. Which do you want?
Melting Slicks
Joined: Jul 2010
Posts: 3,176
Likes: 633
From: perth western australia
Doesn't the Elwood unit come with adapters so you can just plug in your existing hardlines ?
It's just an expensive light weight thing that does the same as an oem unit.
If your going serious track racing with a large fuel tank you might use a manual bias control , if not then the factory set up will still be good for what most people would want.
Just my opinion
It's just an expensive light weight thing that does the same as an oem unit.
If your going serious track racing with a large fuel tank you might use a manual bias control , if not then the factory set up will still be good for what most people would want.
Just my opinion
Race Director
Joined: Mar 2016
Posts: 14,299
Likes: 8,103
From: Napa Valley California
Call Wilwood and ask their service techs.
When I purchased my Wilwood brakes they told me there was no need to change to a proportioning valve unless I was track racing my car with serious chassis and suspension modifications.
When I purchased my Wilwood brakes they told me there was no need to change to a proportioning valve unless I was track racing my car with serious chassis and suspension modifications.
Tech Contributor
Joined: Aug 1999
Posts: 15,135
Likes: 3,939
From: Connecticut, USA
Most seem to think this a pressure adjusting switch to bias pressure between the front and rear calipers. Then again some think you can tighten the lash screw on the steering box and back it off 1/4 turn and it is adjusted.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
The proportioning valve does a little more than just trigger a switch & warning light. It has a metering valve in the front of the unit and a pressure spring in the rear. In the event that either the front or rear brake system fails, loss of pressure, I believe the spool or piston is to shut off the faulty brake line so as to have the capability to still have pressure in half the system. Or a proportion of the brake fluid is blocked off until repairs can be made.
I have a diagram of the internal workings of the prop valve in my profile photo album.
The prop valve can not bias the amount of pressure going to the rear such as those needed on a disc / drum setup. That would be an adjustable type, often having a **** on the unit to tweak the braking system.
I have a diagram of the internal workings of the prop valve in my profile photo album.
The prop valve can not bias the amount of pressure going to the rear such as those needed on a disc / drum setup. That would be an adjustable type, often having a **** on the unit to tweak the braking system.
Last edited by HeadsU.P.; May 25, 2019 at 07:47 AM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
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Tech Contributor
Joined: Aug 1999
Posts: 15,135
Likes: 3,939
From: Connecticut, USA
Not to start an argument with anyone or anyplace, but that Eckler part is a not a proportioning valve. It is a remake of the original pressure diff switch. The pin contact is in the center of the spool in the switch. If the spools shifts from pressure loss, it makes contact and powers up the red dash brake lamp. This just reflects the way parts are sold today compared to years ago.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Not to start an argument with anyone or anyplace, but that Eckler part is a not a proportioning valve. It is a remake of the original pressure diff switch. The pin contact is in the center of the spool in the switch. If the spools shifts from pressure loss, it makes contact and powers up the red dash brake lamp. This just reflects the way parts are sold today compared to years ago.
Anybody know how to tie a noose?
Last edited by HeadsU.P.; May 27, 2019 at 07:21 PM.