If your booster is failed there are threads on the site detailing the replacement parts.
I'd start by making sure you actually have a check valve at the booster, VS a a plain 90deg plastic elbow. (like mine had)
https://shop.advanceautoparts.com/p/...ck-valve-80190
If you have a non-check valve elbow you lose all your built up vac boost each time you go back to idle.
Mine still works so-so as I only have 11in of vac (still better than the solid roller I removed which had 9in.) But the brakes are adequate and will lock up if need be.