If the rear brake pump on the Audi A6 exhibits abnormalities, the first step is to check for any damage to the piston skirt of the rear brake cylinder.
If there are issues with the brake cylinder piston, there is no need to panic; loosen the bleed screw on the cylinder and carefully inspect the rubber ring of the cylinder piston for any damage.
If the rubber ring is intact, apply some brake fluid around the secondary cylinder's rubber ring and finally return it to its original position.
The brake pump is a crucial component of the braking system, responsible for pushing the brake pads against the brake drum to reduce the vehicle's speed. When the driver presses the brake pedal, the master cylinder generates pressure, sending hydraulic fluid to the slave cylinder, which causes the piston within the slave cylinder to operate under hydraulic force, thus pushing the brake pads.
The hydraulic brake system consists of the master brake pump and the brake fluid reservoir, with one end connected to the brake pedal and the other to the brake lines. Brake fluid is stored in the master brake pump and has both an outlet and an inlet.
When the brake is pressed, the outlet opens while the inlet closes. Under the pressure of the pump piston, brake fluid is expelled from the pipes, flowing to various brake cylinders to create braking force.
When the brake pads are released, the outlet in the master pump closes and the inlet opens, allowing brake fluid to flow back from each brake slave cylinder to the master pump, returning to its original state.
For the A6 model, when the upper chamber of the master brake pump opens, the lower chamber also opens, allowing high-pressure gas to enter the quick-release valve and distribute to the brake cylinders of both the front and rear wheels.
When the driver releases the brake pedal, the upper and lower air chambers close, and the pistons of the front rapid intake valve and the rear follow-up valve return to their original position under spring action.
The front and rear brake cylinders are connected to the atmosphere of the air chamber, and the push rod returns to its position, completing the braking process.
Generally, the rear wheels brake first, followed by the front wheels, which helps the driver control direction more effectively.