Brake proportion valve issue

[Dezzracer]

Hello. I recently did a frame off restoration on this 1976 GMC. This included a complete rebuild of braking system and while we were at it, we replaced the 43 year old brake proportioning valve although it was working fine.
The first new one sprung a leak in an area that cannot be fixed. The second one lasted 2 months then locked up the rear brakes one day almost causing me to wreck a brand new and expensive build. We ended up putting the 43 year old original one back in and it works fine. New OEM units are no longer available.
Anybody else have issues with the brass “China made” replacement proportional valve? Seems really odd that I would get too bad ones in a row.

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[fast 99]

Some of the offshore reproduction parts are crap. Correction, most of it is.

I always fall back on: If it aint broke don't fix it.

 

[Nonstop]

I have gone through 3 or more of them on different builds. They all leaked on me. I went to either OEM or Wilwood valves. No more of the brass ones for me.

 

[Ricko1966]

I don't replace something if it works anymore,the chances of the new one being as good as the original are about nil. I will rebuild,repair,recondition an original part if I can before I'll use aftermarket parts. I hear all the time but a new one is cheap,just buy a new one.

 

[GTX63]

I sell very little from trucks I acquire for parts. I cover them and keep them around for issues just like above.

 

[Ricko1966]

I sell very little from trucks I acquire for parts. I cover them and keep them around for issues just like above.

Me too, that's how the tax man got me.

 

[ali_c20]

I run 3 summit brand brass valves, all work, no leaks. Oldest one since 9 years.

 

[Ricko1966]

I run 3 summit brand brass valves, all work, no leaks. Oldest one since 9 years.

Pic? Part number?

 

[ali_c20]

Disc/disc: SUM-760185

https://www.summitracing.com/parts/sum-760185

Disc/drum: SUM-760186

https://www.summitracing.com/parts/sum-760186

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[Ricko1966]

I just looked 760186 wasn't listed for a square or anything after 81. Is it what you are running? I've wondered if the car and truck proportioning valves were the same. I have often wonered.

Disc/disc: SUM-760185

https://www.summitracing.com/parts/sum-760185

Disc/drum: SUM-760186

https://www.summitracing.com/parts/sum-760186

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[ali_c20]

I just looked 760186 wasn't listed for a square or anything after 81. Is it what you are running? I've wondered if the car and truck proportioning valves were the same. I have often wonered.

Yes I run it on my 79 k5 and the disc/disc on my 74 c20. They fit with the original brake line routing and the bolt holes in the crossmember. I think they are all the same as gm tries to use 1 part for 689 applications.

 

[leverhead]

I used Inline Tube brass valve part# PR102 for 71-77 disc drum. Made in USA. Has oem connect for brake light.
Was 79$.

Make sure to have on hand the prop valve plug/tool on hand to bleed the brakes properly .

75 k5 blazer

Hope this helps