Leon,

There is a method (I used it recently) to set the injector pump using the "locked pump method", this is in the Mercedes Maintenance Manual. Perhaps the first mechanic was trying this method.

Although there is a special tool, I fabricated one myself. The pump is locked with the tool, and the engine is set to 15 degrees after top dead center, (15 ATDC) #1 cylinder. The pump is then slipped into position, further "fine tuning" may be required.

Yes those vacuum lines that are accidently separated cause many a head ache.