Originally Posted by
Terrys
This is not the first time I have heard this complaint, and while I'm not familiar with the 2.5NA Vacuum pump, I have heard, or, recall hearing someone say they put in an accumulator, Teed off the line from the vacuum pump to the brake booster. When you are at an engine idle speed, a worn pump will not produce what it will when rev'd up.
The old Jag sedans used a small steel vacuum tank, and there are accumulators that look like and egg carton. I suppose if you want to keep it stock, you had better look into a rebuild kit for the pump. It's not the sort of thing the regular stateside suppliers would stock, but Blanchards, in the UK ought to be able to help you.