The oil line attaches to the rear of the oil filter housing if I remember correctly, and it's a sure bet the plastic part of the vac line with all the supply nipples on it is brittle -- probably got crunched while fitting the oil line (especially if they didn't open the hood all the way!).

That's the only think I can think of that would reduce the vac that much -- just a couple small lines broken won't affect the brake booster much.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!