I've been around the block sorting out the brakes on my Skylark. now the vacuum booster will not hold vacuum. The booster is a dual 9", 4 yrs old. i tried several different bore size, masters cylinders off and on. did i damage a seal? just wondering how it's leaking before i buy a new one. it's not the check valve! wondering if i should open it to have a look for a problem... Cheers!
