Author Topic: Brake proportion valve system (?)  (Read 1611 times)

Offline 1967KaiserM715

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  • 1985 GMC K1500 w/ 6.5 TD
Brake proportion valve system (?)
« 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?



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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« Last Edit: August 30, 2017, 04:33:13 PM by 1967KaiserM715 »
Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline VileZambonie

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Re: Brake proportion valve system (?)
« Reply #1 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.
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Offline 1967KaiserM715

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Re: Brake proportion valve system (?)
« Reply #2 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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Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline 1967KaiserM715

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Re: Brake proportion valve system (?)
« Reply #3 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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Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline 1967KaiserM715

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Re: Brake proportion valve system (?)
« Reply #4 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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Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)