When troubleshooting your vacuum system you must know where the hoses and lines go
What's wrong with my Mercedes?
Different from the 116 / 123 chassis and more difficult to troubleshoot
Double check for damage and use a product to scare them away
Look for the cause in the drive mechanism
If the hoses are leaking or are not hooked up properly a number of problems could occur.
Pump mechanisms breaking apart and piston bolt failures
Common concern on 1980 to 1985 Mercedes Diesel 240D, 300D, 300CD, 300TD