1991 - 300 TD automatic
 

Braking question.

I want to buy a '91 300TD automatic transm. When I toke it for a testride,
it was behaving very well but when braking - at a moderate speed and
gently braking - there was a light "shaking" in the front wheels.
The seller pretends it is rust on the front discs as the car stood still for a
month of two.
Has someone experience with this? What can I expect as repairs?
Could it be misallingement, tyre pressure uneven or worse?
The car has 347000km say 217000 miles and well maintained.
Thanks in advance, MB friends!

Sounds like it probably just needs new rotors. Usually this type of shimmy is caused by warped rotors. Plan on a brake job - new pads/rotors. You can pull a wheel off and see how much rotor and pad is left. If you do the work yourself then you can probably get by with less than $200 for parts. I don't know what it would cost to pay to have the work done.
You will want to have the wheel bearings repacked while doing the rotors.