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Home >> Audi >> 2017 >> A4 Prestige >> Repair and Diagnosis (Single Page) >> Brakes >> Anti-Lock Brakes >> Hydraulic Brake Components >> 47 Hydraulic Components >> Hydraulic System >> Leak Test

Leak Test

Special Tools And Workshop Equipment Required 

High Pressure Test: 

-- Remove the bleed screw at one of the front brake calipers. Connect the Brake Pressure Gauge:VAG1310 A  and bleed.

-- Insert the Brake Pedal Actuator: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 VOLKSWAGEN GROUP OF AMERICA, INC.

-- 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 bar (14.5 psi) during a test period of three minutes.

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