I am converting from front power drum to front power disk on my 69 vert. I purchased all of the parts for the conversion, even that pricey little "hold-off" valve mounted under the master cylinder! :rant: I am assuming that this valve is all I need to regulate the brake fluid properly for the disk brakes, and that I use this along with the current distribution block mounted on the frame. Am I correct? o No: I am under the impression that 70 and later cars combined the hold-off valve and the distribution block, therefore eliminating the seperate hold-off valve. Any help would be greatly appreciated, as I have finished restoring the frame, and I will be ready to reassemble the suspension/brakes soon! :grin:
'71 & later GM's integrated the metering valve into the distribution block & called it a combination valve or proportioning valve. Using such later prop valves on earlier cars will, at the least, require bending up your own lines to the disc brake master cylinder. On several '68 & '69 GTO's I've changed over to disc, I went with full set of '71 A-body disc brake lines when I had the bodys off the frame. Then I used a good used '71-72 A-body prop valve (non station wagon). '67-69 GM factory disc used a distribution block mounted on the frame or under the mastercylinder (F & X-bodys) in combination with a metering valve... the style with the big nut. '69 F bodys also incorporated a holdoff valve in the rear brake line, near the rear of the subframe. '70 GM A-bodys with factory disc utilized the no big nut style metering valve along with a brass holdoff valve on the front side of the rear frame crossmember, right up stream of the rubber hose going to the r/e. Restoring a '69 A-body & have correct '69 lines, stick with the stock pieces, ie, a good early metering valve & repro disc brake lines, if you've ordered them. Good luck. :3gears: Roger
Thanks for responding Roger. So if I understand you correctly, I should use the hold-off valve I bought (with the big nut on the front) and the stock distribution block which is mounted on the driver's side of the frame near the transmission linkage for the column shift. I did run all new factory correct brake lines that are set up for disc brakes, so everything should bolt up pretty well.
