Brake Fluid

I’m looking for the brake fluid reservoir in my 1966 Mercedes 250. Also, what type of fluid should I put in there? Anything special?

1966?? The reservoir is probably part of the master cylinder…DOT 3 Brake Fluid should be fine…But with a Benz you never know, so I would check first. Is this a daily driver or are you trying to resurrect a car that’s been in storage?

Yes. 1966. I’ll take another look. I’m used to working on newish American cars. It is not a commuter car, but it could be. So, I feel a little turned around when I stare at this thing. It is in really good shape. It had one owner and has paperwork trailing to the Motherland. It’s a second car.

My brother said DOT 4, but this thing is so old that I don’t know. It’s ten years older than I am. lol

I appreciate your help. I may take pictures and post them if you think that would help.

I used to own a '66 Mercedes 230, a car virtually identical to yours. And I still have the repair manual!

The reservoir is sitting directly atop the master brake cylinder. The book specifies “ATE Blue, or fluid meeting SAE.70.R.3, same fluids as for clutch.”

As I recall, I used DOT 3 brake fluid. I had to use DOT 4 only for the British sports cars I owned and for nothing else.

Excellent. Thank you!

Let me know if you want to sell your manual. I could use it. Thanks

You may contact me at

DOT 3 and DOT 4 brake fluid are compatible with each other…There is very little difference between them…