proportioning valve

Old Dec 6, 2021 | 04:23 PM
  #1  
glent's Avatar
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Glent
 
Joined: Nov 2021
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From: Ga
proportioning valve

71 Cutlass 455 with Hooker Pro Comp headers now proportioning valve to close to headers. How to move the valve. post pictures please. Causing issues with braking.
Old Dec 6, 2021 | 06:28 PM
  #2  
Vintage Chief's Avatar
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From: Earth
This issue repeatedly surfaces w/ regard to headers and the brake combination valve - far too much heat causing any assortment of issues. The combination valve contains a proportioning valve, a metering valve, a pressure differential valve and an electrical connector brake switch (which remains centered in the pressure differential valve under normal operating conditions e.g. no brake light illumination on dash).

I don't have a picture. There are many areas to reposition and mount the current combination valve or a new combination valve. Many have mounted them elsewhere along the frame and some have mounted them (with a bracket) below the master cylinder. It is not a difficult job to reposition the combination valve. The difficulty lays in the amount of time & labor required to install new brake lines once a new location has been determined. Any location will work as long as the combination valve resides below the master cylinder. Vendors sell brackets for mounting combination valves, they also sell packages (including a new combination valve) with new hard lines leading from the new combination valve (with double flares). No matter how you cut the mustard, you're going to need new hard brake lines from any location you choose. They sell adapters for accommodating fittings, as well.

NOTE: Before removing the current combination valve (if you intend to reuse it), be certain you employ a pressure differential valve bleeder tool to keep the pressure differential valve in its centered position. You'll need the bleeder tool in order to bleed the brakes once you've relocated the combination valve.

Depending on whether you have disc/disc or disc/drum, you can purchase combination valve kits and assorted valve hard lines from various manufacturers to help make the relocation job a little easier. You can buy hard brake lines most anywhere. Be certain to use the proper double flares for brake lines and/or adapters during relocation. Here are a couple links for you.

Again, you can buy these items through many vendors and for various prices. Good luck.

Proportioning Valve Centering Tool
Universal Combination Valve Kit - Disc/Drum Applications

Old Dec 7, 2021 | 07:11 AM
  #3  
oldsonharmont's Avatar
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From: Glendale, AZ
It might help to try some header wrap near the proportioning valve. You can order it from Speedway or Summit and any exhaust shop would install it for you.
Old Dec 7, 2021 | 08:47 AM
  #4  
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On my 70 Cutlass w 455 and disk brakes I just unbolted the valve from the side of the frame and moved it to the top of the frame. I bolted the bracket to an existing hole(I believe for a four speed Z-bar). I left the lines connected and moved it by hand. If you’re careful and go slowly you you should be able to do it without kinking any lines and you won’t need to bleed the brakes after.
Old Dec 8, 2021 | 12:23 PM
  #5  
glent's Avatar
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Glent
 
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From: Ga
Thank you however I cannot get the bolts out because of the headers to try this Its that close
Old Dec 8, 2021 | 12:34 PM
  #6  
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From: West Hartford, CT
Originally Posted by 4speed455
On my 70 Cutlass w 455 and disk brakes I just unbolted the valve from the side of the frame and moved it to the top of the frame. I bolted the bracket to an existing hole(I believe for a four speed Z-bar). I left the lines connected and moved it by hand. If you’re careful and go slowly you you should be able to do it without kinking any lines and you won’t need to bleed the brakes after.
Same procedure followed here on multiple cars. You’re gonna have to remove that header to do it. Header may be able to remain in place if you end up making new lines to/from valve.

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Old Dec 8, 2021 | 01:22 PM
  #7  
Vintage Chief's Avatar
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From: Earth
Originally Posted by glent
Thank you however I cannot get the bolts out because of the headers to try this Its that close
Buy a new combination valve. Cut the lines to/from current combination valve. Leave current combination valve in place, Mount new combination valve. Done.
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