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Proportioning Valve Removal

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Old 12-29-2011, 05:03 PM
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Silver00V6Camaro
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Default Proportioning Valve Removal

Ok well I know this has been discussed before, but since I can not search the archives to find the threads I am going to ask. Who has removed the proportioning valve. Mine has decided it wants to leak and thats the last of the brake puzzle that has not been replaced. My car is a 75. As I understand it 75 up has a valve on the back of the brass block. If this brake system has been the same since 63 when the technology was introduced in the c2 then can I remove the proportioning valve all together and the brakes still work. Also for those that have done it besides some unions, T's and brake line what else is needed. Thanks
Old 12-29-2011, 05:58 PM
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mapman
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Originally Posted by Silver00V6Camaro
Ok well I know this has been discussed before, but since I can not search the archives to find the threads I am going to ask. Who has removed the proportioning valve. Mine has decided it wants to leak and thats the last of the brake puzzle that has not been replaced. My car is a 75. As I understand it 75 up has a valve on the back of the brass block. If this brake system has been the same since 63 when the technology was introduced in the c2 then can I remove the proportioning valve all together and the brakes still work. Also for those that have done it besides some unions, T's and brake line what else is needed. Thanks
Most folks just replace the distribution block/switch assembly they are around $120 from several vendors. Aside from the brake failure (warning light) switch function, the rear brake proportioner improves front-to-rear brake balance at high deceleration.

(Weight transfer to the front during rapid deceleration reduces rear traction and can result in rear wheel skid. The proportioner part of the combination valve reduces the rear brake pressure and delays rear wheel skid.)
Old 12-29-2011, 06:11 PM
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Silver00V6Camaro
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thanks. I do not have any warning lights. Took out all the factory stuff and have autometer guages and custom made turn signal and high beam indicators. So no idiot lights for my car. With that said 120 plus shipping is ridiculous for this part.
Old 12-29-2011, 06:29 PM
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Originally Posted by Silver00V6Camaro
thanks. I do not have any warning lights. Took out all the factory stuff and have autometer guages and custom made turn signal and high beam indicators. So no idiot lights for my car. With that said 120 plus shipping is ridiculous for this part.
The problem IS NOT the warning lights. The problem is regulating brake line pressure to the rear brakes. Without some means of proportioning (reducing) rear brake pressure, the rear brakes will lock up and skid. The proportioning valve is to delay the onset of rear brake lockup.

Last edited by mapman; 12-29-2011 at 09:17 PM.
Old 12-29-2011, 06:32 PM
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Silver00V6Camaro
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Then I should be able to buy one from summit for about 30 bucks and plumb it in.
Old 12-29-2011, 09:36 PM
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would this one work http://www.summitracing.com/parts/CLP-PV-2/ it looks the same as the one on the vette.
Old 12-29-2011, 10:02 PM
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Only 2 places they can leak, the switch oring and the proportioning valve relief.

You can unscrew the proportioning valve from the differential valve and then gut the prop valve inside. Then you must put a pipe plug in the hole on the side. Cost is about an hour and less than a buck for the allen pipe plug.
This will essentially give you the same valve as an earlier C3 or C2 and the front/rear will still be separate circuits for safety.
Old 12-29-2011, 10:11 PM
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Originally Posted by noonie
Only 2 places they can leak, the switch oring and the proportioning valve relief.

You can unscrew the proportioning valve from the differential valve and then gut the prop valve inside. Then you must put a pipe plug in the hole on the side. Cost is about an hour and less than a buck for the allen pipe plug.
This will essentially give you the same valve as an earlier C3 or C2 and the front/rear will still be separate circuits for safety.
That would be a lot cheaper and easier. If I am following what you are saying I just need to unscrew the part that the rear line goes in and then gut it and get a pipe plug.
Old 12-29-2011, 10:56 PM
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Yes
Do a search on here, there are some posts on it.
Old 12-29-2011, 11:01 PM
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Sounds simple. I take it I will need to tap the vent hole for the plug.
Old 12-30-2011, 12:58 PM
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Originally Posted by Silver00V6Camaro
...With that said 120 plus shipping is ridiculous for this part...
Originally Posted by Silver00V6Camaro
...I should be able to buy one from summit for about 30 bucks and plumb it in...
Suit yourself. It's your car.

Old 12-30-2011, 01:43 PM
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Yup and I did what noonie suggested. I don't feel the need to get raped by the vendors just because it is a corvette and pay a premium. Its that same in the musical instrument world you pay for the name.
Old 12-30-2011, 01:47 PM
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[...you can take a horse to water....]
Old 12-30-2011, 02:35 PM
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Originally Posted by mapman
The problem IS NOT the warning lights. The problem is regulating brake line pressure to the rear brakes. Without some means of proportioning (reducing) rear brake pressure, the rear brakes will lock up and skid. The proportioning valve is to delay the onset of rear brake lockup.
I thought the proportioning function only started with the '78s.
Old 12-30-2011, 02:43 PM
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Originally Posted by Mike Ward
I thought the proportioning function only started with the '78s.
Nope, I'm having a new proportioning valve replaced right now, on my 75 Vert. Bought it from Zip Products for $99.95. I thought about going through Summit Racing to get a universal valve, for about $45.00, I figure....to go FAST is one thing, but to SAFELY STOP is FAR MORE important....so the brakes is one area I don't monkey with...if it calls for a certain part, I get that part...$100 is pretty cheap insurance compared to a life of paralysis, or lawsuits out the ying-yang...just because something failed in my braking system because I used a "non stock" or universal part....Just my opinion....

Last edited by vetteguy75; 12-30-2011 at 02:45 PM.
Old 12-30-2011, 03:56 PM
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Default 1974

Originally Posted by Mike Ward
I thought the proportioning function only started with the '78s.
Mike,
My '74s have them.

Regards from Down Under.

aussiejohn
Old 12-30-2011, 04:00 PM
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Mike Ward
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Was '74 the first year then? '73s definitely don't have any proportioning function, only the distribution block and warning switch.

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Old 12-30-2011, 05:14 PM
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Originally Posted by Mike Ward
Was '74 the first year then? '73s definitely don't have any proportioning function, only the distribution block and warning switch.
Mike,

Actually the 1974 does have a proportioning valve.

https://www.paragoncorvette.com/p-35...ing-valve.aspx
Old 12-30-2011, 05:35 PM
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Many vendors use incorrect and misleading terminology for this part- including Paragon. Here's the valve for '70-'73 cars that most certainly has no 'proportioning' capabilities.

https://www.paragoncorvette.com/p-35...ing-valve.aspx
Old 12-30-2011, 05:50 PM
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Default Ooops!!!

Originally Posted by Mike Ward
Many vendors use incorrect and misleading terminology for this part- including Paragon. Here's the valve for '70-'73 cars that most certainly has no 'proportioning' capabilities.

https://www.paragoncorvette.com/p-35...ing-valve.aspx
Mike,
I now think that you're correct. It looks like my cars have the distribution block with the warning light switch down on the chassis, not sure now if it's a prop. valve or not.

My apologies.

Regards from Down Under.

aussiejohn


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