Audi 80 Quiz
Brake System

Troubleshooting

In this manual: Brake System
Technical Description — 39Engines — 41Exhaust System — 13Cooling System — 28Fuel tank and fuel pump — 12Air Filter and Intake Ducts — 13Mono-Motronic Injection System — 18Digifant Injection System — 19KE-III-Jetronic Injection System — 35MPI and MPFI Injection Systems — 32Clutch — 11Transmission and Driveline — 21Suspension and Steering — 33Brake System — 41Anti-lock brake system — 8Wheels and Tires — 13Body Electrical System — 35Ignition System — 24Lighting — 14Signaling Devices — 7Instruments and Auxiliary Equipment — 54Heating and Ventilation — 7Body Components — 18Troubleshooting — 6Specifications — 13
~2min read

Malfunction Possible Cause Remedy
A. Vehicle pulls to one side when braking 1. Uneven tire pressure
2. Uneven tire tread
3. Brake pads contaminated with dirt, oil or unevenly worn
4. Guide pins in disc brake caliper dirty or corroded
5. Piston in disc brake caliper or wheel brake cylinder seized
6. Brake pads not seating correctly against drum
7. Brake discs scored or too thin
8. Distorted brake drums
9. Swollen brake hoses		 Correct on cold tires
Replace tires
Replace pads
Clean
Clean of corrosion or replace
Check and, if necessary, install new brake pads
Replace brake discs
Machine or replace
Replace hoses
B. Brakes squeal 1. Incorrect pads fitted
2. Dust and dirt in disc brakes or drum brakes
3. See A 4, 5, 7 and 8		 Fit original pads
Remove pads, clean off contamination
C. Brakes knock and lock 1. See A 5
2. Protruding rivets on linings
3. See A 8
4. Brake shoe return springs too weak
5. Brake disc runout		 Replace
Replace
Replace
D. One or all wheel brakes overheat 1. Compensating port in master cylinder blocked
2. No free play between brake pedal (pushrod) and master cylinder piston
3. Disc brake calipers seized
4. Parking brake does not release fully
5. Broken return spring (drum brake)		 Clean
Adjust
Have repaired
Check parking brake cables and rear wheel brakes
Replace
E. Brake pedal travel too long, pedal feels soft and spongy 1. Air in brake system
2. Leak in brake system
3. Defective master cylinder
4. Vapor bubbles in old brake fluid under heavy brake load (overheating)
5. See A 5		 Bleed air from brake system
Carry out leak test
Replace
Replace brake fluid
F. Poor braking effect with high pedal effort 1. Normal pedal travel: pads contaminated with oil or glazed
2. Short pedal travel: brake booster defective
3. Long pedal travel: one brake circuit not working due to leak		 Replace
Check
Check, replace damaged parts
G. Parking brake acts on one side only or too weakly 1. See description under A
2. Parking brake cable seized
3. Adjusting mechanism defective		 Replace
Check

Test yourself

A quick Audi 80 quiz: every answer comes with an explanation and a link to the manual page.