1991 - 300 TD automatic

[95300YDT-A]

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!

[engatwork]

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.