So I purchased a complete front drum to disc setup from CPP a couple years ago and installed for a friend of mine. The pedal was always hard, as if there is no assist. At the time it was a 283 and pulled around 18" at idle. Car has a vacuum bank.
Last month I swapped in a mildly built 383 small block, with a 700R4. Brakes are still hard and I have the time to fix it, so I started diagnostics.
So far-
* Checked clearance of pushrod from booster to master. .010"
* Checked for air leaks on Booster with a gauge. Booster is sound
* Removed and checked Master for leaks. None
* Tested assembly in vehicle with a vacuum pump and gauge installed. At 28" it still acts as if there is no assist. The pedal is only slightly easier to apply.
* The CPP supplied proportioning valve is installed and centered
* The car, under no circumstances will lock up the brakes

I called CPP with my issue and spoke with Danny, who agreed with the diagnostics of a bad booster. I purchased the components at a local hot rod shop and and Danny said just go swap it out, they would handle the warranty.
Dreamers no questions asked, swapped out my components, with no hassle. I wholeheartedly applaud this company for it's understanding and willingness to help where it can, great customer service.
Now, onward. New Booster installed, pedal is slightly better feeling, but brake feel and performance are nowhere near expectations. Like I said, it will not lock up even on a smooth concrete floor. I will hook up pressure gauges today to check applied pressure, but what about pedal feel?
I do not want to randomly return components, even under warranty. It is costly to both the company and to the person attempting the repair.
Any pointers will be appreciated-
Thank You all
Matt Ringer
425.239.5562