With regenerative braking doing most of the work and pads lasting for years, it is tempting to think an EV's brake system is maintenance-free. But the brake fluid still needs changing. Here is why EVs need brake fluid service.
Fluid ages by time, not use
Brake fluid absorbs moisture from the air whether or not you use the brakes hard - see why brake fluid absorbs water. So even though an EV's friction brakes are used lightly - see why they last longer - the fluid still degrades on a time-based schedule.
Moisture still corrodes the system
Absorbed water lowers the fluid's boiling point and corrodes the expensive ABS and brake-by-wire hardware from the inside; see brake-by-wire. EVs have complex, costly brake actuators that old fluid can damage, so keeping the fluid fresh protects them.
Follow the maker's interval
Change EV brake fluid on the manufacturer's schedule - often every couple of years regardless of mileage; see brake fluid change interval and hybrid brake fluid. Do not skip it just because the pads are barely worn.
The rest still needs eyes
Along with fluid, have the pads, rotors, and calipers inspected for rust and sticking. When the friction pads finally reach their limit, fit quality pads and hardware.