1980 240D won't turn off!!!

I recently bought this car and yetsreday couldn't get the engine to shut down. Iturned it off manually. I have been told this is a vacuum supply problem. The brakes are fine so I don't think it's the pump but both the door locks and turn signals are on the fritz. The car was just in for a diagnostic 2 weeks ago & the mechanic didn't mention anything about the vacuums. How big of a problem is this to fix and how much should I expect to pay. I live in Berkeley CA where everything seems to be more expensive