Proportioning valve

[overtimeracing]

Does anybody have an idea as to where each brake line goes on the proportionoing valve? I'm not sure I got it right. Thx for the help... Kevin

[Corts60]

Are the lines not pre-bent for the unit? I know there are two or three 1/8" lines and two or three 3/8" lines right?

[SCOTI]

Originally Posted by overtimeracing

Does anybody have an idea as to where each brake line goes on the proportionoing valve? I'm not sure I got it right. Thx for the help... Kevin

The prop valves on 73-87's attach on the splash apron in front of the motor. Looking @ the motor....
The outlet on the side facing the driver frame rail is the front driver supply.
The outlet on the bottom of the p-valve is the pass front supply.
The outlet facing the pass side frame rail is the rear line supply (one common line that splits @ the rear axle).

The inlets from the master cyl are the 2 ports at/near the top of the p-valve.

[N2TRUX]

Originally Posted by SCOTI

The prop valves on 73-87's attach on the splash apron in front of the motor. Looking @ the motor....
The outlet on the side facing the driver frame rail is the front driver supply.
The outlet on the bottom of the p-valve is the pass front supply.
The outlet facing the pass side frame rail is the rear line supply (one common line that splits @ the rear axle).

The inlets from the master cyl are the 2 ports at/near the top of the p-valve.

Anyone have a clear pic that we could add the this info? It would make a great 73-87 FAQ.

[powerdriver 1958]

This is a quick pic , I really think a trip to the salvage yard would be better .

1984 C30



1984 K20


1974 K10

[SCOTI]

Originally Posted by N2TRUX

Anyone have a clear pic that we could add the this info? It would make a great 73-87 FAQ.

Working on it.

[N2TRUX]

Thanks....

[overtimeracing]

Those are excellent pictures guys. thanks alot... Kevin

[SCOTI]

1) Front pass side
2) Front driver side
3) Supply from master cyl to fronts
4) Supply from master cyl to rear
5) Rear common

[N2TRUX]

Thanks to Scot, Dave and all involved. This will soon be in the FAQ forum.

[JNJchev77]

Originally Posted by SCOTI

1) Front pass side
2) Front driver side
3) Supply from master cyl
4) Supply from master cyl
5) Rear common

Scoti, do you know the typical size fitting for #5? I am running all new lines, front is done, and I have the rear set up but my 3/8 fitting does not seem to want to screw into the #5 port? Threads look fine on the Prop valve. I did pick it up from a yard, and the external fitting is brand new. Also, rear line is 1/4 inch, stepped down form the 3/8 fitting... Sorry to steal the thread, but could be helpful here too I guess...

[SCOTI]

Originally Posted by JNJchev77

Scoti, do you know the typical size fitting for #5? I am running all new lines, front is done, and I have the rear set up but my 3/8 fitting does not seem to want to screw into the #5 port? Threads look fine on the Prop valve. I did pick it up from a yard, and the external fitting is brand new. Also, rear line is 1/4 inch, stepped down form the 3/8 fitting... Sorry to steal the thread, but could be helpful here too I guess...

It is an 'odd' fitting. I do have the exact size but don't have the info in front of me. I'll get it for you & post it up once I have my 'notes' in front of me tonight.

[JNJchev77]

Thanks Scoti, I appreciate the help!!

[SCOTI]

That rear fitting is a 9/16-18 port to a standard 1/4" Domestic brake line.

[JNJchev77]

Thanks Scoti, now the search for the fitting!

[SCOTI]

Originally Posted by JNJchev77

Thanks Scoti, now the search for the fitting!

I've found short pieces of line w/it attached @ Oreilly Auto Parts (<$5) or in a 10 count pack @ Advanced Autp Parts; zilch elsewhere. I had my fitting re-plated to match the remaining fittings.

[JNJchev77]

Ya, looks like a very odd fitting. Thanks for the tips!

[JNJchev77]

Something like this?? Amazon.com: IMPERIAL 90171 CYLINDER BRAKE FITTING...
well so much for that working...

[LostMy65]

This Pic helped me:

[LostMy65]

Just found this at another forum:

[LostMy65]

pasted:

The front port on the m/c connects to the front top port on the combination valve. It's a 1/4" line, and has a 1/2-20 oversize nut on the m/c and on the valve.

The rear port on the m/c connects to the rear top port on the valve. On the m/c there is a 9/16-18 oversize nut, 1/4" line, and a 7/16-20 nut on the valve (standard fitting for a 1/4" line).

The port on the angled surface at the front of the valve, and the port on the bottom front of the valve are 3/8-24, standard for 3/16" line. These 2 ports are for the front brakes.

So - 1/4" line and appropriate nuts from m/c to valve. 3/16" line and standard nuts for the front brakes. 1/4" line and a standard nut for the rear brake line.

[LostMy65]

Here's the fitting needed to connect the 79 chevy truck's rear port of the combination (proportioning) valve to the 60-66 brake lines:



Posted via Mobile Device
Posted via Mobile Device

[83GMCK2500]

This weekend I swapped backing plates from 11" to 13" on my 9.5" 14 bolt, do I need to swap proportioning valves?

[JNJchev77]

Originally Posted by LostMy65

Here's the fitting needed to connect the 79 chevy truck's rear port of the combination (proportioning) valve to the 60-66 brake lines:



Posted via Mobile Device
Posted via Mobile Device

Just an fyi for some who are looking for this fitting.... I found it at autozone. I looked all over on-line, napa, etc. Check autozone or orielly's if your having trouble.

[SCOTI]

Originally Posted by 83GMCK2500

This weekend I swapped backing plates from 11" to 13" on my 9.5" 14 bolt, do I need to swap proportioning valves?

You might need to verify you have the correct wheel cylinder for the brakes. They use different wheel cylinders for the C10's standard 2"w vs the HD 2.75" w drum brakes so it might be worth verifying.