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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: 1967KaiserM715 on August 30, 2017, 04:23:03 PM

Title: Brake proportion valve system (?)
Post by: 1967KaiserM715 on August 30, 2017, 04:23:03 PM
Have a major leak on my truck, part of the proportion valve system, what is this plug thing?

(https://uploads.tapatalk-cdn.com/20170830/5e9eb6b2d4c2f44ba022d1fdba3fb98f.jpg)

I can't recall exactly what proportion valve this was, but pretty sure it was the most recommended one.

Plus any ideas on a fix? Or do I need a new valve box?

Thanks

Sorry, also truck is a 1985 GMC K1500, 6.5 diesel, SM465, Hydro boost brakes

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Title: Re: Brake proportion valve system (?)
Post by: VileZambonie on August 30, 2017, 06:02:56 PM
Did you do a disc brake conversion? Is it dry above? If you are certain that is where the leak is coming from then you need to replace it.
Title: Re: Brake proportion valve system (?)
Post by: 1967KaiserM715 on August 30, 2017, 07:26:04 PM
Stock brakes, it is dry above, you can see weep from that spot visibly, I originally thought it was the top line, but it had looked dry, hence I removed the valve to get a closer look.

I'll look into replacing it, but what exactly is that for? Nothing I've seen before, plus I don't see it in pictures online.

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Title: Re: Brake proportion valve system (?)
Post by: 1967KaiserM715 on August 30, 2017, 08:56:37 PM
So the valve is a Classic Performance part CLP-PV-2, purchased last March(2016), while 90% of the reviews are good, the 8% I read that gave bad reviews said that they kept getting bad valves right from the start.

Is there another brand of valve I could use? Or am I better just bypassing? Getting an adjustable Wilwood?

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Title: Re: Brake proportion valve system (?)
Post by: 1967KaiserM715 on April 08, 2019, 04:17:14 PM
So I'm on my fourth proportion valve, last one was luckily a replacement for the third but now it's past 6 months, they won't credit it. It still leaks from that stupid vent plug whatever wichamacallit doohickey thing.

 I had not driven the truck all winter, and checked all fluids except the brakes. They were hard, and it stopped well. I only needed it for a couple days until I could replace the pinion yoke on my other truck. Well, today I thought the brakes felt a little odd, so I checked the fluid level, and sure enough the rear was dry, all the lines seem dry, it's just were that vent thing is.

What is the best fix??

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