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Home >> Audi >> 2021 >> A4 Quattro Premium Plus, 2.0L Eng VIN B >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Hydraulic Components (Brake System) (2 Of 2) >> 47 Hydraulic Components >> Hydraulic System >> Leak Test

Leak Test

Special tools and workshop equipment required 

High Pressure Test

-- Remove the bleeder screw at one of the front brake calipers. Connect the :VAG1310A  and bleed.

-- Insert the :VAG1869/2  between the brake pedal and driver seat. Apply pressure to the brake pedal until the pressure gauge indicates a pressure of 50 bar (725 psi). The pressure must not drop more than 4 bar (58 psi) during the test period of 45 seconds.

Fig 1: Brake Pedal Depressor VAG 1869/2 Inserted Between Brake Pedal And Driver's Seat
GWWA44-0020Courtesy of AUDI OF AMERICA, LLC

-- Replace the brake master cylinder if the pressure decrease is too high.

Low Pressure Testing

-- Set the brake pedal actuator back far enough that the pressure gauge indicates 6 bar (87 psi) positive pressure.

-- The pressure must not drop by more than 1.0 bar (14.5 psi) during a test period of 3 minutes.

-- Replace the brake master cylinder if the pressure decrease is too high.