Shrinking rubber.

See if the locks will hold without the vac reservoir (under driver's front fender or in rear bumper). If so, replace the rubber fittings on the tank. Also check for cracks.

If it still leaks off, you will have to do it the hard way, one door at a time.

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!