I am going to install a front disc brake conversion kit on my dad's 69 GS this winter. The goal is to make this look as close to original as possible which is where I am looking for some guidance from the V8Buick experts. In the garage I currently have the following specifically for a 69 that originally came with front disc brakes: - complete stainless steel brake line kit - brake fluid distribution block which mounts on the frame - front spindles / rotors / calipers / pads / everything that bolts to the front suspension My question comes down to the master cylinder configuration. Did the factory install a proportioning valve? Looking around online I see varying pictures and some of which have a proportioning valve appear to be aftermarket. Along the same lines I see some of the front disc brake kits come with a valve where others do not. I would think they did have a proportioning valve, but really not sure. OPGI sells an OEM master cylinder for the 69-72 Skylark which originally came with front disc brake cars: https://www.opgi.com/skylark/1969/brake-systems/master-cylinders-boosters/CH27375/ If anyone has a picture of how the master/booster looks like in a factory front disk brake car that would be ideal as well.
The 1969 disc brakes will have one valve down on the frame,and an additional valve mounted next to the master cylinder. The original master cylinder also has bleeders. The OPGI one is not correct. Inline Tube has the correct master cylinder and upper valve. The valve that is currently down on your frame is correct,so reuse it. That was the same for 68-70 drum and disc. The factory would add the second upper valve and the different master cylinder,for the disc applications. Beginning in 1971,they figured-out how put everything in one valve,for discs,and put it down on the frame.
