Your vehicle has power-assisted brakes that adjust automatically through normal usage.
If the engine is not running or is turned off while driving, the power assist for the brakes will not work. You can still stop your vehicle by applying greater force to the brake pedal than typical. The stopping distance, however, will be longer than with power brakes.
When the engine is not running, the reserve brake power is partially depleted each time the brake pedal is applied. Do not pump the brake pedal when the power assist has been interrupted.
Pump the brake pedal only when necessary to maintain steering control on slippery surfaces.
WARNING
Take the following precautions:
Hyundai Elantra AD (2016-2020) Owners Manual: Bright-metal maintenance, Underbody maintenance
Bright-metal maintenance
To remove road tar and insects, use a tar remover, not a scraper or other
sharp object.
To protect the surfaces of brightmetal parts from corrosion, apply a coating
of wax or chrome preservative and rub to a high luster.
During winter weather or in coastal area ...
Hyundai Elantra AD (2016-2020) Owners Manual: Good Braking Practices
WARNING
Whenever leaving the vehicle or parking, always come to a complete stop and
continue to depress the brake pedal. Move the shift lever into the 1st gear (for
manual transmission vehicle) or P (Park, for Intelligent Variable Transmission (IVT)/
dual clutch transmission vehicle) position ...