4F0615403A is the Reference number of electronic brake caliper,and the supplier is vika. The detailed information of 8R0823480A is as follows:
Name:electronic brake caliper/rear left
Reference OE number:8R0823480A
Applicable models of 4F0615403A:
Audi: A6 05-08/A6AR07-11/A6Q05-08
How to determine if an electronic brake caliper needs to be replaced?
The caliper is a very important component in a disc braking system. While the brake pedal on a car is pressed, the piston moves under hydraulic force and pushes the brake pad, which in turn gets into contact with the rotor surface and causes the car to decelerate. A caliper failure may lead to some significant negative consequences. The symptoms and the defective part should be first identified before any replacement.
Open the engine hood and check the level of the master cylinder. A leaky piston, bleeder, or brake hose may cause reserve liquid to be drained from the master cylinder. If necessary, immobilize the master cylinder with clean brake liquid.
Start a test drive for the purpose of caliper diagnosis. Try to select a parking lot or a road with few pedestrians. Please make sure your brake pedal is firm before starting. Never attempt to drive the car if the brake pedal fails to react adequately or falls onto the floor.
Drive the car at 30 miles per hours, and then step on the brake pedal firmly. Determine if the car pulls right or left in the course of braking. Such phenomenon clearly indicates that the caliper piston is stuck and only one side of the caliper functions normally.
Drive the car for 10 to 15 minutes and brake it frequently in this course. Next, drive it back to the repair site for further diagnosis. Before troubleshooting, put a bare hand near every wheel equipped with a caliper. Do not touch the wheels, as a stuck piston may have severely heated the brake and nearby components and consequently burn your hand. A burning brake will give off strong heat and a pungent burning smell. If the wheels are indeed very hot, cool them down before proceeding to the next step.
Lift the axle of the car with a suspicious caliper with a jack. Make sure it sits safely on the jack.
Use a lug wrench to loosen the wheel nuts and remove the wheel.
Remove two caliper guide bolts with a ratchet and a suitable sleeve.
Pry the caliper off the rotor with a small crowbar. Some types of caliper contain an integrated pad, while in other types the pad will remain in the caliper anchor.
Check if the caliper exhibits any visible sign of leakage. The leakage of brake liquid is always easy to identify. Inspect the piston area, bleeding screws, and braking hose connection thoroughly. The rubber protective sleeve around the piston should also be examined. A crack on the caliper boot does not necessarily indicate a failure of the caliper, but it will eventually damage the piston. Check if the brake hose has any significant crack or rubber fissure.
Hang the caliper on a hanger bracket with a caliper hook or a steel wire hanger. Use a C-clamp or a caliper piston reset tool to compress the piston. For some rear disc calipers, a reset tool is required to screw the piston into the hole. By contrast, a C-clamp is needed to compress the piston into the hole for the majority of front calipers. The compression process should be slow. If the piston fails to reach the bottom of the hole or is unable to bear the compression force, it is already damaged. In this case, the caliper should be repaired or replaced.