I have rebuilt and restored the midland-ross power brake booster in my '67 mustang using a rebuild kit. Meticulously cleaned painted and reassembled the booster exactly as per my dissassemby photos, diagrams, and youtube how-to videos and reinstalled. However the booster still doesn’t work. I’ve checked all vacuum hoses for leaks, checked hose vacuum with an accurate vacuum gauge indicating (solid 18 in (Hg) or better vacuum, yet booster doesn’t work. Pressed on the brake pedal and found that engine rpm slowed and ran a little rough and then also heard a hissing sound right near the brake pedal pushrod. Pulled back the pushrod boot and could hear the hissing coming from the booster rear hub (where the brake pedal pushrod enters the booster). As mentioned the booster kit was reassembled and triple checked for accuracy along with red rubber grease applied to all the appropriate booster valve locations. The only thing different from the original booster was that I primed and painted all outside and inside metal surfaces with rust paint as the original booster surfaces had rusted here and there. Sure would appreciate any input that might explain what might be causing the problem the problem. Thanks in advance.
Questions:
Is this booster the original from this car?
Is the car an original FACTORY power brake car?
Is this a conversion of some sort?
Possibly the inner seal is backwards?
Thanks for the suggestion… I will take a look at the inner seal to make sure it’s installed correctly. Very much appreciate your response.