Checking the tightness of the accumulator check valve (Audi 100 C3)

Connect the test pressure gauge in the same way as for checking the air pressure in the pressure accumulator.

Let the engine idle until maximum pressure is reached, then stop the engine.

Reduce the pressure to approximately 135 kg/cm² by pressing the brake pedal several times.

The pressure should not fall below 130 kg/cm² within 5 minutes. If the pressure drops by a large amount, replace the pressure accumulator due to a leaky check valve.

Relieve the pressure by pressing the brake pedal several times.

Disconnect the test pressure gauge, replace the hydraulic fluid pressure indicator lamp sensor, and bleed the brake hydraulic system to remove air.

(The text is based on materials from the website: AudiManual.ru)