I'm pissed... I put my disc rear in almost two weeks ago, I've been driving without the right prop valve in since then... I asked the guy who I bought the rear from if he had the prop valve, he said yes, and sent it to me.. I get it, and I go to put it in, and it's the wrong size threads.. he said it came from a 1990 car.. mine's a 1991.. should be the same thing right? do the valves look different from the pre-88's and 88+? I'm wondering if it was from an 87 or something.. here's some pictures of what I have.

 

and here's the one he sent me... can anyone verify from the pictures what style (year range) the valve came from?

 

From the looks of it, it's the same as the one in my 83 T/A.

And yes, the theads did change somewhere around 85-86,IIRC!

 

I believe they changed the brakes in 88.. which would mean this prop valve is from a pre-88 car.. it doesn't make sense though, cause the guy says it's from a 1990.. even if the rear is from pre-88, the prop valve would probably still be 88+ unless he wanted to change all the steel lines and fittings... hell if I know... so now who wants to sell me a 88+ disc brake prop valve for cheap?

 

That's definately a prop valve from pre-85.

If it's an 82-83 prop valve, it'll have standard threads instead of metric threads.

(All '84 up prop valves and -all- brake equipment used metric ISO "bubble" flare fittings for -all- GM cars.)

 

Hey you know a brand new one is only $90 from GM, right?

 

actually, GMpartsdirect.com has them for $50 (plus S&H, which should be $7.95 on something that small) ...

 

Yep i got mine from gm partsdirect for 58.26 w/shipping.The prop valve you received is the early cast iron type.GM switch to the alum one in 86 or so.Also gm change thread pitch.In 89-92 the pitch is steeper than 84 1/2 to 88,but only on the 2 top fittings for m/c to prop valve lines.Plus the early 82-84 use different flaring on lines.heres a pic from andys z28 cd

 

hey im doing the same swap...i got a '88 GTA rear in a 86 T/A...will the 88 prop valve fit the 86 fittings?

 

They should be the same according to the info in the pic.When i switch to 1le brakes using the valve in pic over my stock 84 Rr disc vavle.It bolted staight in,brakes fitting & all.Only had to slightly bend 1 or 2 brake lines to line up to prop valve fittings.