We had the original booster rebuilt but when installed on the car the brake peddle locks up. Requires removing master cylinder to relieve vacuum and release the peddle. We have adjusted the rod by measuring the distance from the master cylinder seat to bore face, bore face to housing surface. Results in booster rod length of 1.125" which should not place any preload on the master cylinder. Had to isolate (unhook) the reserve vacuum tank due to a leak. Have installed a Chevrolet booster with a much different rod length that works but it's not original. Suggestions please...

So after posting this I discussed with a mechanic who advised that even though I am setting the rod to the derived measurement, I am still probably pre-loading the MC due to improper pedal adjustment. I will give this a try and update this post accordingly.

Still seeking input from forum members.
rebuilt brake booster



rebuilt brake booster



Camaro booster



firewall side of Camaro booster in back, rebuilt Olds (Morraine) front left



Camaro booster (note rod is very short)



Master cylinder (bought new from NAPA)