Proportioning valve - The 1947 - Present Chevrolet & GMC Truck Message Board Network

overtimeracing · 05-08-2011, 12:25 AM

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** · 05-08-2011, 01:38 AM

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 · 05-08-2011, 01:51 AM

Quote:

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** · 05-08-2011, 12:10 PM

Quote:

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 · 05-08-2011, 12:35 PM

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

1984 C30
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1984 K20

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1974 K10

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SCOTI · 05-08-2011, 04:45 PM

Quote:

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** · 05-08-2011, 06:49 PM

Thanks....

overtimeracing · 05-08-2011, 08:12 PM

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

SCOTI · 05-09-2011, 10:03 AM

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** · 05-09-2011, 11:38 AM

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

JNJchev77 · 05-09-2011, 12:54 PM

Quote:

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 · 05-09-2011, 01:01 PM

Quote:

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 · 05-09-2011, 01:19 PM

Thanks Scoti, I appreciate the help!!

SCOTI · 05-09-2011, 11:31 PM

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

JNJchev77 · 05-10-2011, 11:38 AM

Thanks Scoti, now the search for the fitting!

SCOTI · 05-10-2011, 11:48 AM

Quote:

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 · 05-10-2011, 11:50 AM

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

JNJchev77 · 05-10-2011, 07:24 PM

Something like this??

Amazon.com: IMPERIAL 90171 CYLINDER BRAKE FITTING...
well so much for that working...

LostMy65 · 01-21-2012, 11:11 PM

This Pic helped me:

LostMy65 · 01-21-2012, 11:58 PM

Just found this at another forum:

LostMy65 · 01-22-2012, 12:01 AM

pasted:

Quote:

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 · 01-24-2012, 10:05 PM

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 · 01-25-2012, 02:51 AM

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

JNJchev77 · 01-25-2012, 11:53 AM

Quote:

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 · 01-25-2012, 11:54 AM

Quote:

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.

05-08-2011, 12:25 AM	#1
overtimeracing Registered User Join Date: Nov 2009 Location: Lakewood, NY Posts: 117	Proportioning valve 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

05-08-2011, 01:38 AM	#2
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: Proportioning valve 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? __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

05-08-2011, 06:49 PM	#7
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,021	Re: Proportioning valve Thanks.... __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

05-08-2011, 08:12 PM	#8
overtimeracing Registered User Join Date: Nov 2009 Location: Lakewood, NY Posts: 117	Re: Proportioning valve Those are excellent pictures guys. thanks alot... Kevin

05-09-2011, 10:03 AM	#9
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,071	Re: Proportioning valve 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 Attached Images __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.* Last edited by SCOTI; 05-09-2011 at 12:59 PM.

05-08-2011, 12:35 PM	#5
powerdriver 1958 Kid's Mechanic Join Date: Nov 2006 Location: Kansas City Posts: 8,241	Re: Proportioning valve This is a quick pic , I really think a trip to the salvage yard would be better . 1984 C30 1984 K20 1974 K10

05-09-2011, 11:38 AM	#10
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,021	Re: Proportioning valve Thanks to Scot, Dave and all involved. This will soon be in the FAQ forum. __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

05-09-2011, 01:19 PM	#13
JNJchev77 Registered Cruiser Join Date: Mar 2010 Location: Mesa, AZ Posts: 918	Re: Proportioning valve Thanks Scoti, I appreciate the help!! __________________ 77' Chevy SB Dropmembered Front and Rear 5.3/4l60e combo

05-09-2011, 11:31 PM	#14
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,071	Re: Proportioning valve That rear fitting is a 9/16-18 port to a standard 1/4" Domestic brake line. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

05-10-2011, 11:38 AM	#15
JNJchev77 Registered Cruiser Join Date: Mar 2010 Location: Mesa, AZ Posts: 918	Re: Proportioning valve Thanks Scoti, now the search for the fitting! __________________ 77' Chevy SB Dropmembered Front and Rear 5.3/4l60e combo

05-10-2011, 11:50 AM	#17
JNJchev77 Registered Cruiser Join Date: Mar 2010 Location: Mesa, AZ Posts: 918	Re: Proportioning valve Ya, looks like a very odd fitting. Thanks for the tips! __________________ 77' Chevy SB Dropmembered Front and Rear 5.3/4l60e combo

05-10-2011, 07:24 PM	#18
JNJchev77 Registered Cruiser Join Date: Mar 2010 Location: Mesa, AZ Posts: 918	Re: Proportioning valve Something like this?? Amazon.com: IMPERIAL 90171 CYLINDER BRAKE FITTING... well so much for that working... __________________ 77' Chevy SB Dropmembered Front and Rear 5.3/4l60e combo Last edited by JNJchev77; 05-10-2011 at 07:42 PM.

01-21-2012, 11:11 PM	#19
LostMy65 But Found Her 25yrs Later! Join Date: Oct 2010 Location: Oregon City, Oregon Posts: 10,530	Re: Proportioning valve This Pic helped me: __________________ I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035

01-21-2012, 11:58 PM	#20
LostMy65 But Found Her 25yrs Later! Join Date: Oct 2010 Location: Oregon City, Oregon Posts: 10,530	Re: Proportioning valve Just found this at another forum: __________________ I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035

01-24-2012, 10:05 PM	#22
LostMy65 But Found Her 25yrs Later! Join Date: Oct 2010 Location: Oregon City, Oregon Posts: 10,530	Re: Proportioning valve 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 __________________ I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035



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01-25-2012, 02:51 AM	#23
83GMCK2500 Registered User Join Date: Sep 2009 Location: Beaverton, OR from WA State Posts: 1,515	Re: Proportioning valve This weekend I swapped backing plates from 11" to 13" on my 9.5" 14 bolt, do I need to swap proportioning valves? __________________ Devin 1983 GMC High Sierra 2500, 4x4, RC/LB, 400 S.B., SM-465, NP-208, Corporate 10 bolt & 9.5" 14 bolt 1996 GMC Sierra SLE 3500 DRW, 4x4, EC/LB, Vortec 454, NV-4500, BW-4401, AAM 925 & AAM 1050 1997 GMC Sierra SLT 1500 4x4, Z71/F44, EC/SB, Vortec 350 My Introduction with my '83s History New Daily, the '96

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