I "think" Duane says the ones being repro'd are for Chevy models....Buick is different.....I know I have the dist valve....hold off will have to come from a salvage car.
1970 used three blocks. A hold off valve located at the master cyllinder, the distribution valve located under the power assist / master cyllinder down on the frame and the proportioning valve is the small one that is in line between the back brake fluid tube and the distribution block mounted to frame also. The hold off valve keeps like 70% of the pedal pressure off the front allowing the backs to do more work so when you apply hard brake pressure, the car does not bite on the front brakes nose diving it; makes for an even stop. The distribution block on the frame does just that; distributes fluid to the front and back. The proportioning valve keeps the back brakes from locking up when full pedal is applied. The system works with distribution block only, but works better as described above with the correct components. The hold off valve that is repopped is for '69- it works just not correct looking. The prop valve and distribution blocks are also repopped. I want a 70 correct hold off valve and if I can find good used for both for less than the new cost, I prefer that route.
In-line tube has all 3 1970 valves. My question is are all three valves used on Buicks? I ask this because In-line said Buick only used the one at the master cylinder. The aft hold off valve was not used. I have found the aft hold off valve on other GM A bodys, but haven't found one on Skylark/GS. The 1970 Buick assemby manual doesn't show one either, but the chevy manual shows it for the Chevelle. Can anyone answer for sure if the aft hold off valve was used on Buicks? Kraig
I think you are right as my 70 GS did not have the aft block, and my buddies 70 chevelle does...I asked the guy at Right Stuff yesterday and he thought BUICK did but could not say for sure. I plan to use the aft block unless someone can tell me it is a bad idea.
Mark..FWIW, I'm certain Buick engineers did extensive testing and IF they decided the AFT block was NOT NEEDED, I say keep it simple. USE what Buick engineers, engineered for our cars! JM.02CW! Wheelz, Tampa Bay
