A hybrid vehicle uses its friction brakes (brakes in the wheels) far less than a conventional vehicle – the hybrid system can use the electric motors to slow the vehicle. Less use means less wear, but less use can also mean more problems down the road. When, then, should you replace the friction brakes on your hybrid?
CARspec recommends brake replacement when:
- The brake pads have 2mm or less lining remaining or the brake shoes (in the case of drum brakes) have less than 1mm of shoe lining remaining.
- The brake rotors and/or drums are excessively rusty on the contact area with the friction material (the brake pad or brake shoe).
- The brake hydraulic system is stuck or seized due to corrosion.
All of the above also apply to conventional vehicles, but hybrid brakes suffer from more corrosion from a simple lack of use: applying the brakes cleans the rotors and drums of water and debris, and less use means less overall cleaning. This lack of self cleaning means more rust, making the rotors less serviceable and more likely in need of replacement.
The up-close photo of the rotor on the left is from the rear of a 2006 Highlander Hybrid at 94,000 miles. The excessive rust on the inside of the friction surface combined with the abnormal grooving of the metal makes the rotors unserviceable. In most cases the rotor can be machined (a small amount of metal is removed from the rotor, exposing clean metal and removing imperfection), but in the example seen here it is too grooved and too rusty to go back into service. In this case the brake pads, shims, fitment kit and rotors were replaced.
There is some good news: while hybrid vehicles may suffer from more corrosion of their brakes, hybrids require brake replacement about half as often as a conventional vehicle. This ends up saving the owner money in the long run. It isn’t uncommon for a Prius to go beyond 120,000 miles before the brakes wear to the point where they require replacement.
We here at CARspec hope this sheds some light on the unique service needs of the hybrid brake system.
