Brake System

Troubleshooting

~2min read

Troubleshooting

Symptom Table

Use the table below to find the cause of the problem. The numbers indicate the priority of the possible causes. Check each part in order. Replace these parts if necessary.
Symptom Suspect area Reference
Pedal sinks or
spongy pedal
1. Brake system (fluid leak)
2. Brake system (air)
3. Piston seals (worn or damaged)
4. Rear brake shoe clearance (not adjusted)
5. Master cylinder (malfunction)
Repair
Bleed
Replace
Adjust
Replace
Brake drag 1. Brake Pedal Free Play (Insufficient)
2. Parking Brake Lever Stroke (Not Adjusted)
3. Parking Brake Cable (Seized)
4. Rear Brake Shoe Clearance (Not Adjusted)
5. Lining or Pad (Cracked or Deformed)
6. Piston (Stuck)
7. Piston (Frozen)
8. Anchor or Shoe (Malfunctioning)
9. Power Assist System (Vacuum Leaks)
10. Master Cylinder (Malfunctioning)
Adjust
Adjust
Repair
Adjust
Replace
Replace
Replace
Replace
Repair
Replace
Brake linkage 1. Piston (sticking)
2. Pad or shoe (greasy)
3. Piston (frozen)
4. Disc (scored)
5. Lining or shoe (cracked or deformed)
Replace
Replace
Replace
Replace
Replace
Hard pedal, but
brakes ineffective
1. Brake system (fluid leak)
2. Brake system (air)
3. Lining or pad (worn)
4. Lining or pad (cracked or deformed)
5. Rear brake shoe clearance (not adjusted)
6. Pad or shoe (greasy)
7. Pad or shoe (glazed)
8. Disc (scored)
9. Brake booster system (vacuum leaks)
Repair
Bleed Air
Replace
Replace
Adjust
Adjust
Replace
Replace
Repair
Brake noise 1. Pad or Lining (cracks or deformation)
2. Mounting Bolt (loose)
3. Disc (scored)
4. Sliding Pin (worn)
5. Backing Plate or Shoe (dirty)
6. Backing Plate or Shoe (glazed)
7. Anchor or Shoe (faulty)
8. Brake Pad Shim (damaged)
9. Pad Retaining Spring (damaged)
Replace
Adjust
Replace
Replace
Clean
Replace
Replace
Replace
Replace
Brake fading 1. Master cylinder (malfunction) Replace
Brake vibration,
pulsation
1. Brake booster (vacuum leak)
2. Brake pedal free play
3. Master cylinder (malfunction)
4. Caliper (damage)
5. Master cylinder cap seal
6. Brake lines damaged.
Replace
Adjust
Replace
Replace
Replace
Replace
Brake Judder Brake vibration is usually caused by loose or worn components, or glazed or burnt pads. Rotors with hard spots may also contribute to brake judder. Other causes of vibration include rotors out of tolerance, brake pads not properly attached to the shoes, loose hub bearings, and contaminated brake pads.

Test yourself

A quick Hyundai Sonata LF quiz: every answer comes with an explanation and a link to the manual page.