There seems to be a lot of confusion about the recommended Mercedes-Benz brake fluid. There is a reason why that is the case. Mercedes-Benz recommends using what is called DOT 4+ brake fluid which does not exist except in the Mercedes-Benz world. The only available brake fluids that you will find at any auto parts store are DOT 3, 4, 5 and 5.1. But no DOT 4 plus.
Recommended Mercedes Brake Fluid
The required brake fluid for your particular model is printed on the cap of the brake fluid reservoir. In most models including E, C, S, CLS, ML, GL, R Class, the recommended Mercedes-Benz brake fluid is DOT 4 plus. Mercedes brake fluid is sold at Mercedes-Benz dealerships. You can also find the OEM fluid from online retailers, see below.