frankenstang 11 Report post Posted January 6, 2013 I just finished replacing the brake booster for the 2nd time on the car. The first one was a factory defect, it had a cracked diaphram. Had absolutely now power to the 4 drums. I just installed a 9" single diaphram Tuff Stuff direct fit booster. Everything went in as good as can be expected. It was a bitch but it is mounted, pedal changed, brakes bled and ready to go. I have strong vacuum (200 ci 6 cyl) so it took it out for a ride. Brakes were 100% better, I felt like they were working properly. Not as soft as the brakes in my '68 but I have front disc/rear drum in that one. Here is the issue, when I initially depress the pedal to stop there is a slight hissing from under the dash by the pedal, when I let off or press harder it goes away. It is not crazy loud and no issues with the engine idle. I have heard that it is not uncommon for a hiss. When I shut the car off I can hear it almost release air. I put a vacuum gauge to it on the front vacuum line and it does hold vacuum. Please tell me I don't have to change it..........Ugh. Quote Share this post Link to post Share on other sites
