20" of vaccum when tested at the pump's inlet .

12" isn't going to do anything .

I hope you've begun the normal ritual engine & chassis cleaning and de greasing because where you're going to be working is always filthy and tiny bits of crud WILL fall in and cause more problems .

Before taking the 'bad' pump off, remove the hard line and then the valve that screws in and check it ~ they fail and/or get cruddy and so cause loos of vacuum when the pump is otherwise still healthy and no need to dismount it .

The pump proper is held to the engine by 5MM ATF hed allen screws and they're always full of dirt, clean them out with a tiny flat screw driver and always tap the Allen wrench or socket (better to use a 3/8" drive Allen socket) before trying to turn them loose .

I'd go check out the Dollar Store typ places for mildew killers ~ read the labels .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better