ASE G1 Auto Maintenance and Light RepairBrakesMedium
A customer reports that their vehicle feels like it is constantly dragging and has decreased fuel economy. The front wheels generate excessive heat after driving, and a burning smell is present. Upon inspection, a technician finds that both front brake calipers are partially seized. What is the MOST likely cause of this issue?
- AContaminated brake fluid causing internal caliper corrosion.
- BWorn wheel bearings allowing excessive rotor runout.
- CA faulty brake booster causing excessive vacuum.
- DImproperly adjusted rear drum brakes.
Show answer & explanationAnswer & explanation
Correct answer: A. Contaminated brake fluid causing internal caliper corrosion.
Partially seized calipers causing drag, heat, and a burning smell indicate that the pistons are not fully retracting. Contaminated brake fluid, especially with moisture, can lead to corrosion within the caliper bore, causing the piston to stick or seize. This is a common cause for both front calipers to be affected.
Why the other options are wrong
- B. Worn wheel bearings typically cause noise (growling/humming) and looseness, not directly seizing calipers or causing constant drag with burning smell from the brakes.
- C. A faulty brake booster typically results in a hard pedal or a sinking pedal, not constant brake drag and heat from seized calipers.
- D. Improperly adjusted rear drum brakes would cause issues at the rear, not both front calipers, and typically wouldn't lead to a burning smell from the front.
Caliper Piston Seizure
Caliper piston seizure, often caused by internal corrosion from contaminated brake fluid, leads to constant brake drag, excessive heat, and decreased fuel economy.
- Corrosion from water in fluid
- Piston fails to retract
- Causes drag, heat, burning smell
Memory trick: Drag and heat, burning scent? Fluid's corroded, the piston's spent!