Brake Pressure Accumulator
If the pressure warning light comes up or the brake force assistance works abnormally, this is a sign of a worn brake pressure accumulator.
Vehicles with a hydraulic brake booster usually consist of the following components: hydraulic pump, brake pressure accumulator (also known as a bomb or brake bomb), and the brake booster itself. The main wearing part is the pressure accumulator, which in most Audi vehicles not only stores pressure but also regulates it. The accumulator (and not the hydraulic pump) sets the system pressure, among other things. A diaphragm and nitrogen are also involved here, and the gas also diffuses into the oil over time in this type of accumulator. The less gas is contained, the less pressure can be provided. If the accumulator is as good as new, it is still possible to perform approx. 20 braking operations with braking force assistance if the drive fails (e.g., engine stalls, drive belt breaks) when the accumulator is fully charged. This, among other things, is a clear advantage over a vacuum brake booster. In the event of an engine failure or a leak in the vacuum system, for example, the latter no longer provides any braking assistance after just one step on the brake pedal.
As long as the internal valves and the diaphragm are intact, we can regenerate these accumulators.