A piece of thin wood. Stick it through and lean on it. Same one I use to push the pistons back in.

Make sure you have the sheild aligned correctly first, though, as it is impossible to get it back out intact, at least for me.

Peter

__________________
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!