Raise the car.
Clean the brake line.
Caution: Brake pipes are coated with a layer of plastic to protect against corrosion. If this layer is damaged, corrosion occurs. Therefore, do not use wire brushes, sandpaper or screwdrivers for cleaning.
Check the lines from the master cylinder to the wheel cylinders using a carrier. The master cylinder is located in the engine compartment under the brake fluid reservoir.
The pipes should not be bent or pinched. They should also be free of rust and abrasions. Otherwise, replace the damaged section of the pipeline.
The tubes are connected to the working cylinders of the wheels on the moving parts of the car by brake hoses. The hoses are made of a material that can withstand high pressure, but over time they become porous, swell and are damaged by sharp objects. In such cases, they must be replaced immediately.
To determine damage, the hose should be bent by hand in different directions. Do not twist the hoses, observe the color marking!
Turn the steering wheel left and right from lock to lock. The brake hoses should not touch any parts of the car.
The connection points of tubes and hoses must not be wet.
Caution: If the reservoir or seals are wet, it is not necessarily a sign of a defective master cylinder. Rather, fluid has leaked through the vent in the reservoir cap or through the cap seal.