Checking the Brake Fluid Level / Low Brake Fluid Warning Light (BMW 5 Series E39)

The expansion tank with brake fluid for the brake system and clutch hydraulic drive is located in the engine compartment. The tank has 2 chambers, one for each brake circuit. The screw cap has a ventilation hole that must not be closed. The expansion tank is made of transparent material, so that the brake fluid level can be checked from the outside at any time. In addition, the driver is informed about the decrease in the brake fluid level below the MIN mark by a warning light on the instrument panel.

However, despite this, it is advisable to regularly visually monitor the liquid level.

Remove the case fine air filters from the driver's side.



The fluid level with the tank cap closed should be no higher than the MAX mark and no lower than the MIN mark.

Use only DOT 4 specification brake fluid.

Due to wear of the disc brakes, the brake fluid level drops slightly - this is normal.

If the level in the tank decreases in a short time, this indicates a loss of brake fluid.

In this case, it is necessary to immediately search for the leak. For safety reasons, the brake system should be checked in a specialized workshop.



Checking the Low Brake Fluid Warning Light

Turn on the ignition, release the parking brake.

Contact in the tank cover press the "arrow" button with your thumb down.

Ask an assistant to check whether the indicator on the instrument panel lights up. If not, check the electrical wiring.

Install the air filter housing finely, see p. 202.

This publication was borrowed from an online resource: BMWMAN