My Vacuum Pump sucks!
 

My 1980 240D has had a problem with the door locks not working and taking a few seconds for the engine to shut off after you turn the key off. I assumed I had a vacuum leak but now the vacuum pump exhaust tube that connects to the air cleaner lid is dripping motor oil. The air cleaner has quite a bit of oil in it so I assume the pump is bad. Can it be rebuilt, am I on the right track?
Any help would be appreciated .