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PEX Aftermarket Brake Wear Sensors

Purpose and Function:

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Brake wear sensors monitor the condition of brake pads and alert the driver when pads reach a minimum thickness. They help prevent damage to the brake disc and ensure timely replacement, maintaining braking efficiency and safety.


Two common types:

  • Mechanical/contact sensors: A small wire embedded in the pad that completes a circuit when the pad wears down.

  • Electronic/optical sensors: Use resistive or capacitive changes, or optical detection, to signal wear without direct contact.

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Features & benefits

  • Provides early warning of worn brake pads, reducing risk of rotor damage.

  • Enhances safety by preventing reduced braking performance.

  • Minimizes repair costs by preventing disc scoring or rotor replacement.

  • Quick and simple to install; many sensors are pre-installed or integrated with the pad.

  • Compatible with ABS/ECU systems for driver alerts on dashboard.

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Technical Highlights

  • Signal types:

    • Mechanical sensors: circuit closes or opens when pad thickness reaches the wear limit.

    • Electronic sensors: output voltage, resistance, or current change to indicate wear.

  • Typical installation: Mounted on the inner brake pad or caliper; sometimes integrated into the pad backing plate.

  • Designed to withstand heat, vibration, and debris generated in normal braking.

  • Minimum pad thickness triggering the sensor varies by OEM; usually around 2–3 mm remaining.

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Diagnostic and Testing Tips

  • Visual inspection: Check sensor wires or contacts for damage, chafing, or corrosion.

  • Continuity test (mechanical sensors): Use a multimeter to verify the circuit closes/opens at minimum pad thickness.

  • Electronic sensor test: Measure voltage/resistance per manufacturer spec; verify the signal changes when pads approach wear limit.

  • Check dashboard warning: Confirm the wear warning light activates at the correct pad wear level.

  • Replace damaged or faulty sensors immediately; check pad condition and replace pads if required.

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Installation Tips and Common Issues

  • Always route wires away from moving parts and heat sources.

  • Ensure sensors are fully seated and secured; loose or misaligned sensors may give false warnings.

  • Never reuse a sensor that has triggered a warning; most are single-use for safety.

  • Check sensor compatibility when replacing pads; some sensors are pad-specific.

  • Mechanical sensors can break if pads are removed roughly; handle carefully during service.

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