Wanted: Chevrolet brake tee junction / connector / fitting

[Alex van de Wetering]

After looking around the website that Phil (thanks Phil!) posted I found a brake tee that looks identical to mine, but uses a different partnumber (594595). The master parts list also uses the same drawing for both partnumbers. (see pics attached). One seems to be used for the 1/2 ton trucks while the other (mine) was originally used on 3/4 ton trucks.

I wonder what the difference could be.....different threads for the brake lines??? or did all chevy's from the period use the same thread on the brake line fittings?......or could it be that the "branch" is different .....is the actual frame thickness different between 1/2ton and 3/4ton trucks???

I asked the obsChevy guys for thread size and overall measurements, but no responce so far.

Alex