Why? You won't be able to stop the car.

Any BMW with no vac booster has hydroboost brakes, not manual unboosted brakes. When the PS pump gets worn, they rattle when the brakes are applied.

To the best of my knowledge, MB has not used hydroboost brakes in automobiles. GM does in trucks.

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!