How do I install an adjustable proportioning valve?

opihinalu

Member
Feb 10, 2021
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Hey all. My stock proportioning valve is leaking out of the rubber plug at the top and I ordered a new adjustable one because those plugs aren't sold. I also ordered 2 7/16-24 Male 3/8-24 Female Inverted Flare Brake Line Adapters because I was told I would need them. I have been looking at this thing for about an hour and I don't understand how I am supposed to install it. I am a complete newbie to brake lines (and pretty much anything in my car), but I know this needs to be replaced and I know I am going to do it myself.
IMG_0003.jpg

This it the proportioning valve I ordered (summit: https://www.summitracing.com/parts/sum-g3906). It is similar to the stock in which the front and rear brake lines go through it. I am going to be completely taking out the other proportioning valve and replacing it. The golden fittings are the 2 7/16-24 Male 3/8-24 Female Inverted Flare Brake Line Adapters and the silver fittings came with the valve and are labeled "supplied 3/8 fittings for 3/16 brake line". First off, the golden brake fittings are too big to thread into the proportioning valve, is this a problem?? The silver fittings do thread into the tops of the golden fittings. Will I need to buy new brake lines? If so should I go with steel or copper? I will need to flare the new brake lines correct? I really do not understand any of this. Any help at all would be greatly appreciated.
 
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7991LXnSHO

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Sep 1, 2010
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Steel lines have a resistance to cracking under vibration copper does not, so regular copper line is out.
Cupronickle is supposed to be easier to bend than steel and more corrosion resistant. For a DIY that you are not trying to match appearance, this sounds good.
I did not look if this is the right size, but this is the type of line that that looks worth a try. You do not need a whole roll. A good length of steel brake line from the FLAPS is probably plenty.
For bending the lines, you will have best luck with a tool that has a spool with machined groves to keep the line from kinking or flattening out. This is a basic one that is inexpensive.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
36,124
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Massachusetts
Is this a stock brake setup? If so, you need to deal with the 3-2 port conversion forst, as you need to put 3 lines into 2 ports.

that prop valve is two inputs, and 3 outputs. 1 to the rear brakes and one each to the fronts.

what is the MC and brake line setup on the car?
 

opihinalu

Member
Feb 10, 2021
70
4
8
18
Florida
Steel lines have a resistance to cracking under vibration copper does not, so regular copper line is out.
Cupronickle is supposed to be easier to bend than steel and more corrosion resistant. For a DIY that you are not trying to match appearance, this sounds good.
I did not look if this is the right size, but this is the type of line that that looks worth a try. You do not need a whole roll. A good length of steel brake line from the FLAPS is probably plenty.
For bending the lines, you will have best luck with a tool that has a spool with machined groves to keep the line from kinking or flattening out. This is a basic one that is inexpensive.
Thanks. Will look into cupronickel lines and that tool. Will I need those fittings and clips and such that those ebay lines come with?
 

opihinalu

Member
Feb 10, 2021
70
4
8
18
Florida
Is this a stock brake setup? If so, you need to deal with the 3-2 port conversion forst, as you need to put 3 lines into 2 ports.

that prop valve is two inputs, and 3 outputs. 1 to the rear brakes and one each to the fronts.

what is the MC and brake line setup on the car?
It is cobra front discs and stock rear drums. Didn't even think of that. How would I do that conversion? The master cylinder and all the brake lines are stock. Would I be better off returning the proportioning valve I ordered and getting a new one that is only for the rear brakes and gutting the old valve? If so, would I still have to do a 3-2 conversion?
 

7991LXnSHO

10 Year Member
Sep 1, 2010
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Thanks. Will look into cupronickel lines and that tool. Will I need those fittings and clips and such that those ebay lines come with?
Each line you make and flare needs a flare fitting put on each end before you flare it. The clips will be needed if you find the steel lines are rusty and you start replacing more than just making adaptor lines.
As stopping is a life and death matter, it there a mentor or car club member that can supervise/help locally?
 
Last edited:

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
36,124
12,040
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Massachusetts
With rear drums, no need to convert. I’m assuming your prop valve and lines are in Decent shape?

here’s what I would do. Return that one

buy this prop valve. It installed on the Union at the firewall

Wilwood 26010922 Break Pad Set Amazon productView: https://www.amazon.com/dp/B019XCGO46/ref=cm_sw_r_cp_api_glt_fabc_2MSVNY88JFK6MYXP1PSS?_encoding=UTF8&psc=1


Remove your leaky front plug, transfer the o-ring over and install this one


all done.
 
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opihinalu

Member
Feb 10, 2021
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Florida
Each line you make and flare needs a flare rotting put on before you flare it. The clips will be needed if you find the steel lines are rusty and you start replacing more than just making adaptor lines.
As stopping is a life and death matter, it there a mentor or car club member that can supervise/help locally?
I see. So the flare fittings are supposed to go into the inverted flare fittings like I ordered correct? I really do not know anyone that would be able to help me with this. I'm 18 and I bought the car a year ago and have been learning to work on it since. I really have only learned from youtube and people here on the forums. I definitely need to branch out and try to find people with knowledge in these cars.
 

opihinalu

Member
Feb 10, 2021
70
4
8
18
Florida
With rear drums, no need to convert. I’m assuming your prop valve and lines are in Decent shape?

here’s what I would do. Return that one

buy this prop valve. It installed on the Union at the firewall

Wilwood 26010922 Break Pad Set Amazon productView: https://www.amazon.com/dp/B019XCGO46/ref=cm_sw_r_cp_api_glt_fabc_2MSVNY88JFK6MYXP1PSS?_encoding=UTF8&psc=1


Remove your leaky front plug, transfer the o-ring over and install this one


all done.
Yep, besides the bad plug, the proportioning valve and lines seem to be in good shape. Got it. Gotta try to find the invoice for the other valve now so I can return it. Thanks.
 

Mustang5L5

i'm familiar with penetration
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Feb 18, 2001
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Do you have a pic of the leaky plug? I just want to make sure I’m giving you the right advice.

leaking from the small center rubber nipple in the front plug?
 

7991LXnSHO

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Edit. Fitting, not rotting. That makes no sense.
The inverted flare fittings are supposed to go directly into whatever the line goes into and seal the line flare against leaks.
 
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Mustang5L5

i'm familiar with penetration
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Feb 18, 2001
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What I said will work and is easier to install.


the prop valve installs in place of the Union on the pass side firewall line. If you get the 3/8-24 version that I linked, just remove the Union and thread the fitting into the prop valve and tighten
 

opihinalu

Member
Feb 10, 2021
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Florida
What I said will work and is easier to install.


the prop valve installs in place of the Union on the pass side firewall line. If you get the 3/8-24 version that I linked, just remove the Union and thread the fitting into the prop valve and tighten
Sounds easy enough. Do I need to gut the stock prop valve if I do that?
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
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Sounds easy enough. Do I need to gut the stock prop valve if I do that?

yes. When you remove that plug, pull the prop valve out of the front. Transfer the o-ring over to the new plug and install. The valve on the firewall will now control the knee-point
 
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opihinalu

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Feb 10, 2021
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Florida
yes. When you remove that plug, pull the prop valve out of the front. Transfer the o-ring over to the new plug and install. The valve on the firewall will now control the knee-point
Sorry to re-open and older thread, but I am just now getting to working on this. Where exactly is the union? I spent a few minutes looking for it but I don't see anything?
 

j753303

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Aug 25, 2020
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i bought the prop eliminator from MM and put a ford racing adjustable where Mustang5L5 is telling you. easy and works great
 
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