High And Low Pressure, Checking

Test Prerequisite

• Function of conventional brake system OK

High Pressure, Checking

-- Remove bleeder screw on one front brake caliper.

-- Connect Brake Pressure Gauge 0-250 Bar:VAG1310A  and bleed.

-- Install brake pedal depressor between driver's seat and brake pedal.

-- Load brake pedal until gauge indicates 50 bar (725 psi).

-- Watch gauge for 45 seconds.

• Pressure must not drop more than 4 bar (58 psi)

If pressure drop is excessive:

-- Replace ABS hydraulic unit.

Low Pressure, Checking

-- Adjust brake pedal depressor so that gauge indicates brake line pressure of 6 bar (87 psi).

-- Monitor pressure for 3 minutes.

• Pressure must not drop more than 1 bar (15 psi)

If pressure drop is excessive:

-- Replace ABS hydraulic unit.