My Delco Moraine brake booster has a cracked vacuum check valve in it. I've tried several places but no one has this particular size which is hard to believe. Everyone I've checked with stocks a smaller size check valve. The booster has a 1-1/8" grommet hole in it, which is bigger than the grommet hole in my original booster (69 Impala). Has anyone run in to this before and why would parts stores only stock the one size. I believe the Delco Moraine boosters were used for multiple years by Chevrolet....maybe I should check with Chevrolet....Scott

There is a line of parts marketed under the brand name "HELP!". Some autoparts stores cary this line. They may have your part. If not try the Chevy garage parts man or a trip to the local bone yard. Good Luck