On my 68 I have installed disc brakes. I have the small P valve that goes under the master cylinder ( see pic below). If I use the P valve fom the later GM vehicles with disc brakes can I eliminate the small valve? Also, does anyone know if these valves are offered new by anyone? Thanks
The "p valve" you describe is called the "hold off" valve. It is for 1965-70 models. In 71, GM switch to the combo (distribution and proportioning) valve. You will need the 71-up combo valve to eliminate the hold-off valve. You will also need new brake line from the front chamber of the master cylinder to the combo valve. New ones are made but they are generic and not correct for "show restos" You should be able to sell yours.
Thanks for the info George. Looks like I'll have 2 to sell. I am not doing a show resto but rather a mild custom so there are several things that are not of original type. Do you have a reccomended source for these new valves? Thanks
Wanna trade valves? I've converted to disks and would like to keep the old proportioning valve but I need the smaller one that you have. Do you also have the 2 lines that connected to both sides of that valve?( 1 to the M/C, other to proportioning valve) I looked at installing the newer version, ( bought it from OPG) but didn't have lines/time/patience and am willing to part w/ it. Will try to return it if not. Thanks!
Chuck Sure I'll trade you. When I got the valves they were in 2 bags. One marked "leaks and the other "untested". Both have the small steel line and a mounting bracket. Let me know if you want them Jim
