Hydraulic Modulator - Hydraulic Pressure Test
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 1989 Audi 90, 1989 Audi 80, 1989 Audi 200, 1989 Audi 100, and 1988 Audi 90. However, it is still accessible from the selected car via links, so may be relevant.
- Remove one front wheel. Remove bleed screw from brake caliper. Connect and bleed Pressure Gauge Set (VW 1310). Press brake pedal until pressure gauge reads 725 psi (51 kg/cm2 ). If pressure drops more than 58 psi (4 kg/cm2 ) in 45 seconds, replace hydraulic modulator. If okay, go to next step.
- Press brake pedal until pressure gauge reads 87 psi (6 kg/cm2 ). If pressure drops more than 14.5 psi (1 kg/cm2 ) in 3 minutes, replace hydraulic modulator.
NOTE:
If the anti-lock indicator light comes on while driving and goes out again by itself after a short time, check voltage supply to ABS control unit at terminal No. 1.