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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: 1967KaiserM715 on March 07, 2016, 04:08:51 pm

Title: Question: Brake Combo/Proportion Valve
Post by: 1967KaiserM715 on March 07, 2016, 04:08:51 pm

Hi all, looking for part numbers, or specs on the combination/proportion valve for a 1985 GMC 1/2 ton truck. I am/will be using a 1 ton Hydro-Boost and master, stock brakes all around(rear 11 3/4 inch drums)

I remember reading that 34-4054 is the part number for the valve, but nothing has come up with my search, and most other valves appear to be for 1977 and down.

I was going to reuse my valve, but it looks like it went bad from sitting-or it was bad, fluid looked terrible when I drained it in the fall.

thanks

Title: Re: Question: Brake Combo/Proportion Valve
Post by: gunrac on March 07, 2016, 04:26:52 pm

http://www.partsgeek.com/

Title: Re: Question: Brake Combo/Proportion Valve
Post by: 1967KaiserM715 on March 07, 2016, 05:54:32 pm

are you trying to give me link to a part? nothing comes up and I tried searching the site with no success.

Jegs and Summit both carry universal valves, but again, they only have those listed as 1977 an down, nothing for 1985(also tried '84 and '86 with no luck)

Will I be fine with one of the disc/drum valves for a 1977? I am making all new lines, so I just need to get fittings, I really just want to make sure it will function right.

Title: Re: Question: Brake Combo/Proportion Valve
Post by: gunrac on March 07, 2016, 06:47:53 pm

I just figured this place would have one......K' here is what I came across:

http://www.partsgeek.com/ss/?i=1&ssq=proportion+valve&x=14&y=12

Title: Re: Question: Brake Combo/Proportion Valve
Post by: 1967KaiserM715 on March 07, 2016, 08:16:09 pm

Tuff country has one listed, $20, but comes with a relocation bracket? From same site as above

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Title: Re: Question: Brake Combo/Proportion Valve
Post by: Bunkerbuilder on March 25, 2016, 01:33:46 pm

I used a disc/drum rpc racing power company dot Com part # R4500.

Oh and personally I don't care for aluminum parts when it comes to the brake parts on my trucks so if you agree with me on this point make sure you don't buy the one that company calls chrome as it not brass that is chrome plated it's aluminum maybe polished maybe chrome plated, but in any case the inverted thread connections on it strip out real easy, brass is a much better part.

I assumed you were speaking of the prop/combination valve that's bolted to the frame crossmember under the radiator core support and not a separate adjustable aftermarket prop valve.

Title: Re: Question: Brake Combo/Proportion Valve
Post by: 1967KaiserM715 on March 25, 2016, 10:36:44 pm

Yes I was talking about that valve on frame, I ended up ordering a PV2 from Summit, think Classic Performance was the manufacture. Just found it odd the cutoff year is 1980, and nothing was listed for 1980 to 1987

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