Team Camaro Tech banner

Brake hold off valve?

4418 Views 1 Reply 2 Participants Last post by  ohcscott
I have a pre X coded 1969 camaro, and when I pulled the rear brake line out it was a one piece line. Then just recently I ordered a new brake line from "The right stuff" and it was a two piece line that required a brake "hold off valve". They said I could either order the one piece line or a two piece, and where both correct for '69. The brake hold off valve is located half way down the body. Supposedly this valve retains residual pressure for the rear so can anyone say why GM went to this and what other, if any other vehicles used it?
1 - 2 of 2 Posts
It's not a hold off valve or a residual valve. It regulates rear brake pressure in proportion to front brake pressure... a proportioning valve. It reduces the rear pressure during hard stops to keep the rears from locking up. It was used on many cars with high front to rear weight differences, such as with big block or A/C.
Pontiac lists it as used "with disc brakes, with A/C" for their Firebird, but Camaro seems to me to be more arbitrary in their useage. The two cars used the same valve, same part number. The rear brakes were made small enough that many cars were expected not to need this valve. It basically does the same thing as the adjustable valves do, but it's not adjustable.

Here's some great info on this valve provided by our moderator, David Pozzi.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.