brake fluid mixed
 

I had the 190E taken for an oil change at the local shop. While that was being done I noticed the brake fluid was a bit low. So I had the mechanic top it off. However I noticed that the fluid he used was wagner DOT 3.
I know the benz is supposed to have DOT 4, my question is will that hurt the braking system ? Should I have it flushed just because there's a bit of DOT3 in the system mixed with DOT4 ?

I'd vote no.
The fluids are compatible.
DOT4 has better properties in terms of moisture absorbtion and boiling point.

OTOH, if you have not flushed in the past year, a flush is a good idea anyways. I confess I often go 2 years between flushes, or whenever my brake pads wear out.

Ditto, don't worry about it.

phew !
thanks for the replies. makes me feel better now otherwise I was getting worried about it.