Brake Pressure Regulator - Modifications

Group: 47
Number: 92-05
Date: December 31, 1992

Subject:
Changes to Brake System

Model(s):
90 Quattro
1993 m.y.

As of model year 1993, VIN 8CPA 008020 the following changes were made:

Brake Pressure Regulator

^ revised version with new switch point
^ new regulator has numeral 35 embossed on face side and is additionally marked by a blue dot.
^ When checking brake pressure regulator note specifications for earlier version as well as revised version regulators.





Brake pressure regulator, checking
- raise vehicle and connect pressure gauge VW 1310 to left front and left rear brake calipers.
- bleed both gauges.
- depress brake pedal to obtain specified pressure at front axle and read pressure for rear axle.

Regulators up to VIN 8CPA 008 019
^ front axle: 50 bar (725 psi)
rear axle: 30 to 35 bar (435 to 507 psi)

^ front axle: 100 bar (1450 psi)
rear axle: 45 to 50 bar (653 to 725 psi)

Regulators from VIN 8CPA 008 020
^ front axle: 50 bar (725 psi)
rear axle: 37.5 to 41.5 bar (453 to 602 psi)

^ front axle: 100 bar (1450 psi)
rear axle: 51.5 to 57.5 bar (747 to 834 psi)

- replace brake pressure regulator if pressure reads outside of specified tolerances.
- disconnect pressure gauges and bleed brake system.