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

PunkRock247 · 01-05-2005, 03:13 PM

Hello,

I am in the middle of switching my 69 from front drum brakes to front disc brakes. I purchased a new front disc proportioning valve. My question is that there is a difference in the number of lines leaving the proportioning valve. As you can see in my picture there are two short lines that go from the master cylinder to the proprtioning valve, that is fine for me. However there are 3 other places for lines (the three black arrows in my picture). I assume that the one in the back is for the rear brakes and that the other two are for the front. However I only have one line going to the proportioning valve for the fronts because there is a union down near the crossmember that splits it off into two for the front brakes. Should I just plug one of the holes in the new proportioning valve or do I need to remove the union and run two seperate lines to each of the front brakes?

Thanks for your help.

Tx Firefighter · 01-05-2005, 03:55 PM

That's not like an original disc brake truck prop valve (71-72 truck). The original type only had the 4 lines like you expect. That must be some type of replacement unit that's also intended for other applications. Can the place you got it from offer any tech advice on this?

PunkRock247 · 01-05-2005, 05:23 PM

To be honest the place I bought it from does not have very good customer service. I was stupid and tried to save a few bucks by going to a place I knew didn't have very good tech support. I really should have bought it through one of the board vendors who has proved to have excellent support in the past. Maybe I will just return it and see if I can't find a used one on the parts board.

PunkRock247 · 01-05-2005, 05:48 PM

Hey Tx Firefighter,

I saw your post HERE and your proportioning valve looks exactly like mine except that mine has that extra "port". I am trying to remember but I thought that 73-up pickups might plumb the lines from each of the front wheels individually which would require them to have the extra line. I guess I can just plug that one and try it out to see if it works before I send it back.

Tx Firefighter · 01-05-2005, 06:31 PM

Disregard the pictures in my old post. That was an S10 prop valve I used. Someone told me they worked fine.

It did not work fine at all. After a few days of head scratching I took it off and put the corect 71-72 prop valve on it and all was well from then on.

avejoe · 01-05-2005, 10:03 PM

What are the odds?

I live in Sacto and am having prop valve problems too. Looking at your picture, I would guess the third port on the top should be plugged. But that's onluy a guess. My 72 1/2 ton has one line to the front with a T under the radiator area.

I am waiting for an original replacement valve off a parts truck that is being shipped from a Board member. Hopefully it gets here by the weekend so I have something to do indoors with the big storm on the way.

old trucks again · 01-05-2005, 11:37 PM

maybe this will help.
http://www.classicperform.com/PVK.html

68w/sbc406 · 01-05-2005, 11:43 PM

i believe that that is a 73 up prop valve. on those years they bolt to the front cross brace on the frame. so you could run two lines to the front brakes if you can join the two lines, but if you want the right stuff, take it back and get one for our trucks

avejoe · 01-05-2005, 11:55 PM

I called Truck Rex in Rocklin yesterday and they have an original one (used) for $50. Call 411 for their #. Chevyland in Rancho has replacements for $80, but they might be the same as the one you have now.

Tx Firefighter · 01-06-2005, 12:00 AM

Quote:

Originally Posted by avejoe

I called Truck Rex in Rocklin yesterday and they have an original one (used) for $50. Call 411 for their #. Chevyland in Rancho has replacements for $80, but they might be the same as the one you have now.

I think a wanted ad on the parts board would be much easier to swallow.

I paid 20 bucks for my 72 prop valve on there. Used of course....but, they don't often fail if they haven't been exposed to the elements.

68w/sbc406 · 01-06-2005, 12:03 AM

whos the vendor in florida ?PICKMUP? thats who i got my prop valve from

69C10 · 01-06-2005, 12:12 AM

Wow I live very close to you guys (punk & joe) Any others near the valley/delta on this board?
Jb

4x4Poet · 01-06-2005, 05:36 AM

The combination valve on my 71 K10 uses the front angled-up pipe thread hole for a bleeder valve. Perhaps mine applies since it's disc brake. I only wanted to point out that that valve you posted looks similar to mine and the "extra" hole is used on my truck for a bleeder valve. I'm not looking at mine right now, though.

I would also recommend using one of this board's vendors for a combo valve if yours proves to be the wrong application. Looks ok to me, but I'm no parts expert.

For reference purposes, Classic Tube offers a combination valve with brake switch for 71-82 GM trucks. Unfortunately, the "view part" link on this page doesn't work. It shows the vehicle application info, though.

MOTHERTRUCKERS · 01-06-2005, 09:54 AM

68w/sbc406 I believe you got that from me if it was new.

PunkRock247 · 01-06-2005, 11:05 AM

Wow, thanks for all of the replies. That was a great link "old trucks again". Confirmed what I was thinking and from their photo it looks as if they sell it with a plug already installed for our trucks. I think I am going to go ahead and try to plug the upper one and see what happens. If that doesn't work I am sure you all will see a WTB on the parts board for a correct proportioning valve. Thanks again everyone, what would I do without this board?

http://www.classicperform.com/product-pages/PVKS.htm

68w/sbc406 · 01-06-2005, 09:03 PM

Quote:

Originally Posted by MOTHERTRUCKERS

68w/sbc406 I believe you got that from me if it was new.

it was used. but i know i got it from florida

chevydog66 · 01-06-2005, 10:12 PM

I am getting ready to put front disc brakes on my 66 Chevelle, and I need one of those wire connections for the brake light that goes in the middle of the proportioning valve. Anyone know where I can get one? Maybe NAPA?

01-05-2005, 03:13 PM	#1
PunkRock247 Registered User Join Date: Dec 2002 Location: Antelope, CA Posts: 44	Proportioning Valve Question Hello, I am in the middle of switching my 69 from front drum brakes to front disc brakes. I purchased a new front disc proportioning valve. My question is that there is a difference in the number of lines leaving the proportioning valve. As you can see in my picture there are two short lines that go from the master cylinder to the proprtioning valve, that is fine for me. However there are 3 other places for lines (the three black arrows in my picture). I assume that the one in the back is for the rear brakes and that the other two are for the front. However I only have one line going to the proportioning valve for the fronts because there is a union down near the crossmember that splits it off into two for the front brakes. Should I just plug one of the holes in the new proportioning valve or do I need to remove the union and run two seperate lines to each of the front brakes? Thanks for your help. __________________ 1969 Chevrolet C-10 SWB Last edited by PunkRock247; 01-05-2005 at 06:37 PM.

01-05-2005, 03:55 PM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	That's not like an original disc brake truck prop valve (71-72 truck). The original type only had the 4 lines like you expect. That must be some type of replacement unit that's also intended for other applications. Can the place you got it from offer any tech advice on this? __________________ I'm on the Instagram- @Gearhead_Kevin

01-05-2005, 05:23 PM	#3
PunkRock247 Registered User Join Date: Dec 2002 Location: Antelope, CA Posts: 44	To be honest the place I bought it from does not have very good customer service. I was stupid and tried to save a few bucks by going to a place I knew didn't have very good tech support. I really should have bought it through one of the board vendors who has proved to have excellent support in the past. Maybe I will just return it and see if I can't find a used one on the parts board. __________________ 1969 Chevrolet C-10 SWB

01-05-2005, 05:48 PM	#4
PunkRock247 Registered User Join Date: Dec 2002 Location: Antelope, CA Posts: 44	Hey Tx Firefighter, I saw your post HERE and your proportioning valve looks exactly like mine except that mine has that extra "port". I am trying to remember but I thought that 73-up pickups might plumb the lines from each of the front wheels individually which would require them to have the extra line. I guess I can just plug that one and try it out to see if it works before I send it back. __________________ 1969 Chevrolet C-10 SWB

01-05-2005, 06:31 PM	#5
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Disregard the pictures in my old post. That was an S10 prop valve I used. Someone told me they worked fine. It did not work fine at all. After a few days of head scratching I took it off and put the corect 71-72 prop valve on it and all was well from then on. __________________ I'm on the Instagram- @Gearhead_Kevin

01-05-2005, 10:03 PM	#6
avejoe Custer had a plan too. Join Date: Dec 2003 Location: No. California Posts: 344	What are the odds? I live in Sacto and am having prop valve problems too. Looking at your picture, I would guess the third port on the top should be plugged. But that's onluy a guess. My 72 1/2 ton has one line to the front with a T under the radiator area. I am waiting for an original replacement valve off a parts truck that is being shipped from a Board member. Hopefully it gets here by the weekend so I have something to do indoors with the big storm on the way. __________________ 72 K15 GMC (aka Big White) Performance Rockers, Cab Corners, and Floors Fossil Fuel Glutton Neighborhood Nuisance 98 BMW 540i for Speed (Sold ) 05 Subaru Outback for mileage

01-05-2005, 11:37 PM	#7
old trucks again Registered User Join Date: Dec 2004 Location: bolinas,ca. Posts: 9	maybe this will help. http://www.classicperform.com/PVK.html

01-05-2005, 11:43 PM	#8
68w/sbc406 Got Light Emitting Diode? Join Date: Apr 2004 Location: Newberg, OR Posts: 2,485	i believe that that is a 73 up prop valve. on those years they bolt to the front cross brace on the frame. so you could run two lines to the front brakes if you can join the two lines, but if you want the right stuff, take it back and get one for our trucks __________________ 1968 1/2 ton 2wd lwb 6 lug disc and bags up front. Next c notch and rear bags '02 Chevy Silverado LT ext cab short bed 2WD 5/7 drop on 22's(the family car) 1993 Cherokee work ride/weekend wheeler

01-05-2005, 11:55 PM	#9
avejoe Custer had a plan too. Join Date: Dec 2003 Location: No. California Posts: 344	I called Truck Rex in Rocklin yesterday and they have an original one (used) for $50. Call 411 for their #. Chevyland in Rancho has replacements for $80, but they might be the same as the one you have now. __________________ 72 K15 GMC (aka Big White) Performance Rockers, Cab Corners, and Floors Fossil Fuel Glutton Neighborhood Nuisance 98 BMW 540i for Speed (Sold ) 05 Subaru Outback for mileage

01-06-2005, 12:03 AM	#11
68w/sbc406 Got Light Emitting Diode? Join Date: Apr 2004 Location: Newberg, OR Posts: 2,485	whos the vendor in florida ?PICKMUP? thats who i got my prop valve from __________________ 1968 1/2 ton 2wd lwb 6 lug disc and bags up front. Next c notch and rear bags '02 Chevy Silverado LT ext cab short bed 2WD 5/7 drop on 22's(the family car) 1993 Cherokee work ride/weekend wheeler

01-06-2005, 12:12 AM	#12
69C10 Registered User Join Date: Dec 2004 Location: Central Valley, CA Posts: 41	Wow I live very close to you guys (punk & joe) Any others near the valley/delta on this board? Jb

01-06-2005, 05:36 AM	#13
4x4Poet Registered User Join Date: Nov 2004 Location: "Under Montana skies." Posts: 1,836	The combination valve on my 71 K10 uses the front angled-up pipe thread hole for a bleeder valve. Perhaps mine applies since it's disc brake. I only wanted to point out that that valve you posted looks similar to mine and the "extra" hole is used on my truck for a bleeder valve. I'm not looking at mine right now, though. I would also recommend using one of this board's vendors for a combo valve if yours proves to be the wrong application. Looks ok to me, but I'm no parts expert. For reference purposes, Classic Tube offers a combination valve with brake switch for 71-82 GM trucks. Unfortunately, the "view part" link on this page doesn't work. It shows the vehicle application info, though. __________________ '71 GMC K20 Suburban, '71 GMC K10 Suburban, '72 Chevy C10 CST Suburban, '72 Chevy K20 clunker pickup. Last edited by 4x4Poet; 01-06-2005 at 05:53 AM.

01-06-2005, 09:54 AM	#14
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	68w/sbc406 I believe you got that from me if it was new. __________________ Rest in Peace Ed. Thanks for all the good times.

01-06-2005, 11:05 AM	#15
PunkRock247 Registered User Join Date: Dec 2002 Location: Antelope, CA Posts: 44	Wow, thanks for all of the replies. That was a great link "old trucks again". Confirmed what I was thinking and from their photo it looks as if they sell it with a plug already installed for our trucks. I think I am going to go ahead and try to plug the upper one and see what happens. If that doesn't work I am sure you all will see a WTB on the parts board for a correct proportioning valve. Thanks again everyone, what would I do without this board? http://www.classicperform.com/product-pages/PVKS.htm __________________ 1969 Chevrolet C-10 SWB

01-06-2005, 10:12 PM	#17
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	I am getting ready to put front disc brakes on my 66 Chevelle, and I need one of those wire connections for the brake light that goes in the middle of the proportioning valve. Anyone know where I can get one? Maybe NAPA? __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up



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