Rear Brake Disc Corrosion and Caliper Slider Seizure
ModerateBrakesBecause the RC 300h uses regenerative electric braking to harvest kinetic energy during deceleration, the mechanical rear friction brakes are lightly stressed during normal UK road use. In damp, salt-treated winter conditions, the rear ventilated discs fail to reach self-cleaning temperatures. Corrosion develops across the friction face, forming raised rust ridges, while road grit causes the sliding caliper guide pins to seize. This leads to brake binding, premature pad taper, and frequent UK MOT test failure.
Deep rust rings, flaking scale, or pitting clearly visible across the rear disc faces, High-pitched brake squeal or grinding noise during low-speed braking, One rear alloy wheel noticeably hotter than the other after motorway journeys due to caliper binding, MOT test failure or advisory recorded for brake disc pitted or significantly weakened
- Visually inspect the outer and inner contact faces of both rear brake discs through the wheel spokes
- Check for excessive heat, brake dust accumulation, or a burning smell from the rear wheels after a test drive
- Roll the car on a gentle incline in neutral to ensure the brakes release freely without drag