Clean the brake pipe.
Attention: The brake pipes are covered with a plastic layer to protect against corrosion. If this layer is damaged, the tubes can rust. For this reason, do not clean the tubes with a wire brush, sandpaper or a screwdriver.
Check with a lamp-carrier pipelines from the main brake cylinder to the wheel brake cylinders. The master brake cylinder is located in the engine compartment under the expansion tank of the brake system.
The tubes must not be kinked or dented. There should be no places covered with corrosion or with abrasions. Otherwise, replace the tubing section up to the next connection.
Brake hoses connect tubes to wheel brake cylinders on moving parts of the vehicle. They are made of high pressure material but can crack, swell or be damaged by sharp objects over time. In such cases, they must be replaced immediately.
Bend hoses by hand to check for possible damage. The hoses must not be twisted. Observe the color markings on the hoses!
Turn the steering wheel left and right as far as it will go. In this case, the brake hoses must not touch the car parts.
The connection points of the brake hoses and tubes must not be wet with brake fluid.
Attention: If the expansion tank and gaskets are wet, this is not at all a sign of a defect in the brake master cylinder. More likely is the leakage of brake fluid through the vent in the reservoir cap or through the cap gasket.