Automotive Service Technician exam: Brake systems

Key points

• Pedal pulsation usually means excessive rotor runout or thickness variation.
• A pull to one side can come from a seized caliper or contaminated pads.
• Brake fluid absorbs moisture, which lowers its boiling point.
• Measure rotor thickness against the minimum stamped on the rotor.
• A spongy pedal usually means air in the system.

Study tip

Pair each complaint with its usual cause and these questions get quick.

Try these

1. A spongy brake pedal most likely means:

   1. Worn rotors
   2. Air in the lines
   3. Seized caliper
   4. Low tire pressure
   Show answer

   B. Air in the lines Air compresses.

2. Pedal pulsation is usually caused by:

   1. Air in lines
   2. Rotor thickness variation
   3. Low fluid
   4. Worn shoes
   Show answer

   B. Rotor thickness variation Uneven rotors push the pistons.

3. Brake fluid is changed regularly because it:

   1. Thickens
   2. Absorbs moisture
   3. Evaporates
   4. Loses colour
   Show answer

   B. Absorbs moisture Moisture lowers the boiling point.

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