You will need an assistant to bleed the brakes. If you need to bleed the entire system, you should do this separately for each of the calipers. If air got into only one of the calipers, it is enough to pump this particular caliper.
Pumping sequence: 1) rear left caliper, 2) rear right caliper, 3) front left caliper, 4) front right caliper.
Remove the boot from the brake cylinder drain valve. Clean the valve, put a clean tube on it. Lower the other end of the tube into a vessel half-filled with brake fluid.
Ask an assistant to press the brake pedal several times so that pressure builds up in the brake system (Each time you press the brake pedal, more and more resistance will be felt).
After creating pressure in the system, you should drown the brake pedal to the stop and hold it in this position.
Using a spanner wrench, open the drain valve about half a turn and collect the spilled liquid in a container. Ensure that the end of the tube is constantly below the surface of the liquid.
After the liquid stops flowing, close the drain valve.
Pressurize the system again by depressing the brake pedal. Press the pedal and, holding it in this position, open the drain valve and allow the liquid to drain, then close the valve again.
Repeat this procedure on one cylinder until the escaping fluid no longer contains air bubbles.
Remove the tube from the drain valve and put the boot on it.
Repeat the above operations on the remaining brake cylinders.
Attention: When bleeding the brakes, constantly monitor the fluid level in the brake reservoir. It must not be allowed to fall too much, otherwise air may enter the system. Always use fresh brake fluid when topping up.
After bleeding the system, the tank must be filled to the mark "max".