Benz started using disk brakes in 1958, I believe, and switched all cars to 4-wheel disks in 1962. The earliest ones were front disk/rear drum, and had a remote booster for the fronts only, but all four wheel disks have had a vacuum booster every since, no exceptions that I know of.

Why do you want manual brakes? They are in no way an improvement.

Cars without vaccum boosters these days have hydroboost, not manual brakes. BMW has used them since the early 70's on the top of the line models, and I'm sure Toyota is doing the same thing.

The only cars with manual disks were very early Chrysler and Ford applications, and they were dropped very quickly due to excessive pedal pressure and pedal travel problems. I've driven a couple, no thanks.

The difficulty is the volume of the reduced size bore in the master cylinder. The pads DO retract quite a bit if the seals are working correctly, and the volume needed to compensate for pad wear, although much less with semi-metallic linings than with asbestos pads, is not insignificant. Having the pedal hit the floor during a panic stop or a steep downgrade is nasty.

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!