Centering proportioning valve. $60 proportion valve, - The 1947 - Present Chevrolet & GMC Truck Message Board Network

AirSpeed · 03-28-2011, 10:47 PM

I just replaced my master cylinder and now I can't center my proportioning valve. I have searched the threads and tried everything I could find trying to get it centered. I tried opening both rear bleeders, both front bleeders, I tried slow pedal pressure, I tried fast pressure, I tried taking off the output lines right out of the prop valve and bleeding it there. Nothing I have tried will work. Is there something I'm missing? I have read that there is a pin on the front of the valve that needs to be held in when bleeding the brakes, I tried that, then I watched the pin while my wife pushed the brakes and the little pin never moves, it looks like it's all the way in. Is this my problem? Is that little valve supposed to be out? Mine is almost flush with the black plastic piece it sticks out of, it sticks out about 1/16".
So I'm confused, is that little steel piece the part that's supposed to be held in when bleeding the brakes? Since mine does not move, could that be why I can't center the valve and get the light out? I am thinking of just buying a new valve, I found one at "truck shop" that is labeled "GM replacement" for $60, have any of you used it? I would rather not spend $130 for one if I can avoid it (assuming I can't center mine)
Thanks for any suggestions and information!
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oldblue1968chevy · 03-28-2011, 10:57 PM

Get lolife to see this thread, the guy is amazing with brakes/suspension..

AirSpeed · 03-29-2011, 12:24 AM

Should I be able to move the little pin in and out, the little pin in the end of the proportioning valve? Mine seems to be in as far as it can go, it does not move when the brakes are depressed. It sticks out about 1/16th of an inch. I tried to pull it out with some pliers, it would niether pull out or go in.

AirSpeed · 03-29-2011, 12:27 AM

Should I be able to move the little pin in and out, the little pin in the end of the proportioning valve? Mine seems to be in as far as it can go, it does not move when the brakes are depressed. It sticks out about 1/16th of an inch. I tried to pull it out with some pliers, it would niether pull out or go in.

RichardJ · 03-29-2011, 03:18 AM

The pin is part of the Metering Valve and has nothing to do with the Brake Light Switch.
If the Metering Valve or Hold-off Valve as it is also called is bad, the vehicle will nose-dive at low speeds with light brake pressure. It prevents pressure to the front disc brakes until the rear brakes reach about 40 psi.

Your Combination Valve includes a Metering Valve, a Proportion valve and the Brake Light Switch.
If one side (front or rear) fails, the pressure from the good side pushes the Switch piston to the other side, which should close off that line out of the conbination valve. That way if the problem is a leaking wheel cylinder, you are not pumping all the fluid out onto the ground.
Have your wife push on the pedal. Crack one of the bleeders, front or rear. If you chose the right end of the truck, the light should go out, as soon as the pedal starts to drop. If that didn't do it, go to the other end of the truck and try again.

If that doesn't work, you still have air in the lines and need to bleed again. Make sure you don't have a leak somewhere.

AirSpeed · 03-29-2011, 01:39 PM

I have bled the brakes six times now, I ran 1 1/2 quarts of fluid through the system. I have read here and in two repair manuals that the pin in the end of the valve has to be held in to bleed them properly, the pin in mine does not move, even when the brakes are pushed, it's almost flush with the end of valve, that's why I am wondering if mine has an issue. I'm trying to figure out if that pin is supposed to move when the brakes are depressed? As I said, mine does nothing so I'm wondering if its possible to bleed them if mine is bad.

I tried the the method you suggest several times with no luck. That's why I'm wondering if they are actually bleeding since the little pin I have been told needs to be held in is bad?
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*stich626* · 03-29-2011, 02:29 PM

whats your problem
the brake light on..
try tapping on the valve with a hammer..

cdowns · 03-29-2011, 03:04 PM

does the light go off if you disconnect the wire? if not the wire is grounded

Alex Hayley · 03-29-2011, 03:12 PM

If I read the entire thread correctly, the issues are the brake light will not go out AND the valve pin does not move. Can't help with the brake light but I had the same issue with the pin. I read a thread that mentioned someone taking the valve apart, fixing the issue only to have the pin get stuck again. I decided to avoid those steps and just replaced the valve with an adjustable valve (http://www.summitracing.com/parts/WIL-260-11179/).

AirSpeed · 03-29-2011, 03:55 PM

Quote:

Originally Posted by cdowns

does the light go off if you disconnect the wire? if not the wire is grounded

It does go out when I disconnect the wire, I checked it with a continuity tester, it's definately the valve.

AirSpeed · 03-29-2011, 03:56 PM

[QUOTE=Alex Hayley;4586483]If I read the entire thread correctly, the issues are the brake light will not go out AND the valve pin does not move. Can't help with the brake light but I had the same issue with the pin. I read a thread that mentioned someone taking the valve apart, fixing the issue only to have the pin get stuck again. I decided to avoid those steps and just replaced the valve with an adjustable valve (http://www.summitracing.com/parts/WIL-260-11179/).[/QU

Are the fittings all the same? I dont want to have a plumbing nightmare if I go that route. Does it connect to the dash light to let you know if theres a problem? Thanks!

AirSpeed · 03-29-2011, 06:39 PM

Well, I gave up and ordered a new combo valve, mine is definately no good.

70c10 · 03-29-2011, 07:10 PM

When I did the disc brake conversion, I had the same problem and somebody on the board told me to stomp on the brake pedal as hard as I could while it was in Park. Sure enough the brake light went right out and re-centered it!

AirSpeed · 03-29-2011, 07:30 PM

Quote:

Originally Posted by 70c10

When I did the disc brake conversion, I had the same problem and somebody on the board told me to stomp on the brake pedal as hard as I could while it was in Park. Sure enough the brake light went right out and re-centered it!

I tried that as well, no luck. I am sure mine has issues, the little pin in the end is stuck and I'm sure now that it's one of the reasons, if not the reason my rear brakes would lock up. I replaced both rear wheel cylinders and replaced the front calipers as well. I also replaced the master cylinder so after I receive the new combo valve I will have an all new brake system. I ended up finding one on EBay, it comes with new lines between it and the master cylinder and new wire harness. It only cost $69 delivered, much better than the $130+ price I found for an OEM style valve. The one I bought is supposed to bolt and plumb up without issue, I sure hope so!
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*stich626* · 03-29-2011, 08:10 PM

a little shot of air in the valve on the side it's stuck on.. and it be back to normal..

AirSpeed · 04-02-2011, 02:43 PM

I received my new combo valve and installed it yesterday. It came with the mount, two pre bent lines to connect it to my master cylinder and the little wire that connects to the warning light. It was a pleasure to install, the pre bent lines fit perfectly. Now my brakes are 100% new and man do they work great. My truck stops effortlessly now, before the rears would lock up and I dont think the fronts were doing anything. It's amazing what that little valve does and how much better it stops now that it's installed. It's the best $69 I've spent all week!
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abranz · 07-12-2011, 12:38 AM

Who did you buy the valve from on ebay? Tony

hot trux · 07-12-2011, 08:27 AM

70c10 is correct. Also bleed at master cyl to center pin if the stomping don't work.

03-28-2011, 10:47 PM	#1
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Centering proportioning valve. $60 proportion valve, I just replaced my master cylinder and now I can't center my proportioning valve. I have searched the threads and tried everything I could find trying to get it centered. I tried opening both rear bleeders, both front bleeders, I tried slow pedal pressure, I tried fast pressure, I tried taking off the output lines right out of the prop valve and bleeding it there. Nothing I have tried will work. Is there something I'm missing? I have read that there is a pin on the front of the valve that needs to be held in when bleeding the brakes, I tried that, then I watched the pin while my wife pushed the brakes and the little pin never moves, it looks like it's all the way in. Is this my problem? Is that little valve supposed to be out? Mine is almost flush with the black plastic piece it sticks out of, it sticks out about 1/16". So I'm confused, is that little steel piece the part that's supposed to be held in when bleeding the brakes? Since mine does not move, could that be why I can't center the valve and get the light out? I am thinking of just buying a new valve, I found one at "truck shop" that is labeled "GM replacement" for $60, have any of you used it? I would rather not spend $130 for one if I can avoid it (assuming I can't center mine) Thanks for any suggestions and information! Posted via Mobile Device Last edited by AirSpeed; 03-29-2011 at 12:25 AM.

03-28-2011, 10:57 PM	#2
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: Centering proportioning valve. $60 proportion valve, Get lolife to see this thread, the guy is amazing with brakes/suspension.. __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

03-29-2011, 12:24 AM	#3
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Re: Centering proportioning valve. $60 proportion valve, Should I be able to move the little pin in and out, the little pin in the end of the proportioning valve? Mine seems to be in as far as it can go, it does not move when the brakes are depressed. It sticks out about 1/16th of an inch. I tried to pull it out with some pliers, it would niether pull out or go in.

03-29-2011, 12:27 AM	#4
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Should the pin in the end of the prop valve move? Should I be able to move the little pin in and out, the little pin in the end of the proportioning valve? Mine seems to be in as far as it can go, it does not move when the brakes are depressed. It sticks out about 1/16th of an inch. I tried to pull it out with some pliers, it would niether pull out or go in.

03-29-2011, 03:18 AM	#5
RichardJ Registered User Join Date: Apr 2010 Location: So Cal Posts: 1,428	Re: Centering proportioning valve. $60 proportion valve, The pin is part of the Metering Valve and has nothing to do with the Brake Light Switch. If the Metering Valve or Hold-off Valve as it is also called is bad, the vehicle will nose-dive at low speeds with light brake pressure. It prevents pressure to the front disc brakes until the rear brakes reach about 40 psi. Your Combination Valve includes a Metering Valve, a Proportion valve and the Brake Light Switch. If one side (front or rear) fails, the pressure from the good side pushes the Switch piston to the other side, which should close off that line out of the conbination valve. That way if the problem is a leaking wheel cylinder, you are not pumping all the fluid out onto the ground. Have your wife push on the pedal. Crack one of the bleeders, front or rear. If you chose the right end of the truck, the light should go out, as soon as the pedal starts to drop. If that didn't do it, go to the other end of the truck and try again. If that doesn't work, you still have air in the lines and need to bleed again. Make sure you don't have a leak somewhere. __________________ '67 GMC 2500, 292, 4spd, AC

03-29-2011, 01:39 PM	#6
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Re: Centering proportioning valve. $60 proportion valve, I have bled the brakes six times now, I ran 1 1/2 quarts of fluid through the system. I have read here and in two repair manuals that the pin in the end of the valve has to be held in to bleed them properly, the pin in mine does not move, even when the brakes are pushed, it's almost flush with the end of valve, that's why I am wondering if mine has an issue. I'm trying to figure out if that pin is supposed to move when the brakes are depressed? As I said, mine does nothing so I'm wondering if its possible to bleed them if mine is bad. I tried the the method you suggest several times with no luck. That's why I'm wondering if they are actually bleeding since the little pin I have been told needs to be held in is bad? Posted via Mobile Device

03-29-2011, 02:29 PM	#7
stich626 Account Suspended Join Date: Sep 2010 Location: hingham ma Posts: 1,721	Re: Centering proportioning valve. $60 proportion valve, whats your problem the brake light on.. try tapping on the valve with a hammer..

03-29-2011, 03:04 PM	#8
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Centering proportioning valve. $60 proportion valve, does the light go off if you disconnect the wire? if not the wire is grounded __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-29-2011, 03:12 PM	#9
Alex Hayley Registered User Join Date: Jul 2000 Location: NC Posts: 987	Re: Centering proportioning valve. $60 proportion valve, If I read the entire thread correctly, the issues are the brake light will not go out AND the valve pin does not move. Can't help with the brake light but I had the same issue with the pin. I read a thread that mentioned someone taking the valve apart, fixing the issue only to have the pin get stuck again. I decided to avoid those steps and just replaced the valve with an adjustable valve (http://www.summitracing.com/parts/WIL-260-11179/).

03-29-2011, 03:56 PM	#11
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Re: Centering proportioning valve. $60 proportion valve, [QUOTE=Alex Hayley;4586483]If I read the entire thread correctly, the issues are the brake light will not go out AND the valve pin does not move. Can't help with the brake light but I had the same issue with the pin. I read a thread that mentioned someone taking the valve apart, fixing the issue only to have the pin get stuck again. I decided to avoid those steps and just replaced the valve with an adjustable valve (http://www.summitracing.com/parts/WIL-260-11179/).[/QU Are the fittings all the same? I dont want to have a plumbing nightmare if I go that route. Does it connect to the dash light to let you know if theres a problem? Thanks!

03-29-2011, 06:39 PM	#12
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Re: Centering proportioning valve. $60 proportion valve, Well, I gave up and ordered a new combo valve, mine is definately no good.

03-29-2011, 07:10 PM	#13
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	Re: Centering proportioning valve. $60 proportion valve, When I did the disc brake conversion, I had the same problem and somebody on the board told me to stomp on the brake pedal as hard as I could while it was in Park. Sure enough the brake light went right out and re-centered it! __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

03-29-2011, 08:10 PM	#15
stich626 Account Suspended Join Date: Sep 2010 Location: hingham ma Posts: 1,721	Re: Centering proportioning valve. $60 proportion valve, a little shot of air in the valve on the side it's stuck on.. and it be back to normal..

04-02-2011, 02:43 PM	#16
AirSpeed Registered User Join Date: Jul 2007 Location: Fall River California Posts: 2,026	Re: Centering proportioning valve. $60 proportion valve, I received my new combo valve and installed it yesterday. It came with the mount, two pre bent lines to connect it to my master cylinder and the little wire that connects to the warning light. It was a pleasure to install, the pre bent lines fit perfectly. Now my brakes are 100% new and man do they work great. My truck stops effortlessly now, before the rears would lock up and I dont think the fronts were doing anything. It's amazing what that little valve does and how much better it stops now that it's installed. It's the best $69 I've spent all week! Posted via Mobile Device

07-12-2011, 12:38 AM	#17
abranz Registered User Join Date: Nov 2009 Location: Osburn, Idaho Posts: 28	Re: Centering proportioning valve. $60 proportion valve, Who did you buy the valve from on ebay? Tony



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07-12-2011, 08:27 AM	#18
hot trux '85 Stepside Join Date: Jan 2006 Location: montgomery city mo. Posts: 360	Re: Centering proportioning valve. $60 proportion valve, 70c10 is correct. Also bleed at master cyl to center pin if the stomping don't work.

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