"To hit the brakes" means to press down on the pedals in a vehicle to make it slow down or stop.
Sentences with «to hit the brakes»
You certainly have to use a tie - down strap for heavy items, or you wouldn't want to be in the front seats when the driver hits the brakes hard. (automobilemag.com)
Many people questioned whether the state should hit the brakes on change. (washingtonpost.com)
When I stop the car (by hitting the brake pedal), the engine all of a sudden stops while on drive. (mechanics.stackexchange.com)