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Automotix DIY provides automotive consumers and do it yourselfers; the most comprehensive repair information about 1991 Audi 90 Quattro car and truck
repair procedures including Audi engine diagrams, wiring diagrams, repair work estimating measures, technical service bulletins, auto body work
guidance, starter & alternator replacement procedures, serpentine belt replacement procedures, radiator & hose replacement procedures, tune-up &
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procedures, fuel filter replacement directions, component location diagrams, air filter locations & replacement instructions, a/c
system specifications, and general auto service procedures. You don't have to be a car mechanic or technician to know how to fix
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BRAKE SERVICE PROCEDURES FOR 1991 Audi 90 Quattro AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 Audi 90 Quattro cars and light trucks from 1990+.
AUDI, HYDRAULIC BRAKE SYSTEM -> CHECKING BRAKE SERVO OPERATING PRESSURE -> 1990-91 100/200
Vehicle: 1991 Audi 90 Quattro 20V 2.3 L5 GAS
1990-91 100/200
Refer to Fig. , when checking operating pressure.
- With engine off, depress brake pedal approximately 20 times to reduce system pressure.
- Disconnect warning light switch electrical connector, then remove switch.
- Attach pressure gauge with hollow bolt and copper washers to brake servo unit. Attach thick copper washer between brake servo unit and banjo fitting and thin copper washer between hollow bolt and banjo fitting.
- Start engine and let idle until pressure gauge reading exceeds 2030 psi.
- If specified pressure is not reached, check delivery rat...
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BRAKE SERVICE PROCEDURES FOR 1991 Audi 90 Quattro AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 Audi 90 Quattro cars and light trucks from 1990+.
AUDI, HYDRAULIC BRAKE SYSTEM -> MASTER CYLINDER REPLACEMENT
Vehicle: 1991 Audi 90 Quattro 20V 2.3 L5 GAS
Refer to Figs. through , when replacing master cylinder.
- Disconnect brake lines from master cylinder.
- R...
CLICK HERE TO GET FULL ACCESS TO 1991 Audi 90 Quattro BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 Audi 90 Quattro AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 Audi 90 Quattro cars and light trucks from 1990+.
AUDI, POWER BRAKE UNITS -> CHECKING PRESSURE ACCUMULATOR CHECK VALVE -> 100/200
Vehicle: 1991 Audi 90 Quattro 20V 2.3 L5 GAS
100/200
- With engine off, depress brake pedal approximately 20 times to reduce system pressure.
- Disconnect warning light switch electrical connector, then remove switch.
- Attach pressure gauge with hollow bolt and copper washers to brake servo unit. Attach thick copper washer between brake ser...
CLICK HERE TO GET FULL ACCESS TO 1991 Audi 90 Quattro BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 Audi 90 Quattro AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 Audi 90 Quattro cars and light trucks from 1990+.
AUDI, DISC BRAKES -> Tightening Specifications
Vehicle: 1991 Audi 90 Quattro 20V 2.3 L5 GAS
CLICK HERE TO GET FULL ACCESS TO 1991 Audi 90 Quattro BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 Audi 90 Quattro AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 Audi 90 Quattro cars and light trucks from 1990+.
AUDI, HYDRAULIC BRAKE SYSTEM -> HEIGHT SENSITIVE BRAKE PRESSURE REGULATOR -> 80/90 -> ADJUSTING -> CHECKING -> PRESSURE CHECK
Vehicle: 1991 Audi 90 Quattro 20V 2.3 L5 GAS
CHECKING
80/90
Brake pressure regulator is mounted on right rear of body and operated by spring attached to rear axle. Test must be conducted with empty vehicle, full fuel tank and driver's seat occupied.
- Firmly depress pedal once (vehicle must be on ground).
- Release pedal suddenly and ensure lever on pressure regulator moves.
PRESSURE CHECK
80/90
- Ensure brake system is properly filled and bled.
- Connect gauge assembly US 1016 or equivalent, to left front and right rear calipers, according to manufacturer's instructions.
- On 90 models, bounce vehicle several times...
CLICK HERE TO GET FULL ACCESS TO 1991 Audi 90 Quattro BRAKE SERVICE PROCEDURES
BRAKE SERVICE PROCEDURES FOR 1991 Audi 90 Quattro AUTOMOBILES
Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported 1991 Audi 90 Quattro cars and light trucks from 1990+.
AUDI, ANTI-LOCK BRAKES -> TROUBLESHOOTING -> ABS RETURN PUMP DOES NOT RUN, RELAY GOOD, TESTER IN POSITION 3 -> ABS RETURN PUMP DOES NOT RUN, TESTER IN POSITION 3 -> LED 1 & 3 DO NOT LIGHT, TESTER IN POSITION 1 -> LED 13 DOES NOT LIGHT -> LED 19 DOES NOT LIGHT -> LED 2 DOES NOT LIGHT -> LED 35 DOES NOT LIGHT -> LED 4 DOES NOT LIGHT, TESTER IN POSITION 1 -> LED 4, 2, 35, 18 & 19 DO NOT LIGHT, TESTER IN POSITION 1 -> LED FOR ALTERNATOR DOES NOT GO OUT WHEN ENGINE STARTS -> LED FOR ALTERNATOR DOES NOT LIGHT, TESTER IN POSITION 2 -> LED FOR BRAKES DOES NOT GO OUT WHEN BRAKE PEDAL IS DEPRESSED -> LED FOR BRAKES DOES NOT LIGHT -> NO RESPONSE FROM SELECTED SENSOR, TESTER IN POSITION 6 -> POWER SUPPLY -> SENSOR SIGNAL ON METER BELOW MINIMUM VALUE -> Solenoid Valve Relay Check -> WRONG SOLENOID VALVE OPERATES, TESTER IN POSITION 5
Vehicle: 1991 Audi 90 Quattro 20V 2.3 L5 GAS
The Bosch ABS 2 LED-Tester or an equivalent Must be used during test procedures. Connect tester per manufacturers instructions.
POWER SUPPLY
- Check battery for full charge.
- Check that fuses 3, 12 and anti-lock brake power supply relay fuses are satisfactory. The anti-lock brake power supply relay fuse is located on top of the power supply relay.
- Check for continuity between ABS control unit connector terminal 13 and ground, at battery ground cable. Fig. .
- Turn ignition switch to the Off position.
- Check for continuity between ABS control unit connector terminal 10 and ground.
- Check for b...
CLICK HERE TO GET FULL ACCESS TO 1991 Audi 90 Quattro BRAKE SERVICE PROCEDURES
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