This is to help people new to Mercedes Benz diesels.
Banjo bolt location on the 1985 W126 300SD:
Rear of intake manifold.
What is it?
A hollow bolt with a hole in the side to give passage.
What does it do?
Pass intake manifold pressure to the ALDA.
Why does it need cleaning?
Oil sludge, carbon and other gunk builds up and plugs the bolt and line.
What happens if the bolt or line are plugged or broken?
Massive power loss.
over tighten the Banjo bolt; you will strip the threads from the manifold.
Follow the line to the ALDA, and remove the Hex banjo bolt from the ALDA, you should clean this bolt and banjo fitting at the same time.