1983 Mercedes Benz 300dt

1983 Mercedes Benz 300dt 6 cyl Two Wheel Drive Automatic 150000 miles

Is there a kit I can buy that will determine where there are leaks in the vacuum system?

The vacuum pump does have the 20-25 inches of vacuum

Currently, I have to manually lock/unlock the doors so I know there's a leak somewhere.

Recently bought this car from a private party.
November 11, 2009.

This is a very common occurrence. The small vacuum lines on the left side of the vehicle next to the master cylinder are the vacuum lines that go to the locks checked those lines, make sure they are in good condition. Also you can take a vacuum attach it to those lines and see if it's holding vacuum.

Dr Loot
Nov 28, 2009.