Why Does a Car Roll on Flat Ground When Parked?
2 Answers
Here are the related explanations for a car rolling on flat ground when parked: 1. Not engaging the handbrake: After parking an automatic car on level ground, the reason for rolling may be not pulling the handbrake. It could be because the vehicle has stopped without first engaging the P gear, and the second reason might be that the electronic parking brake was not activated. To prevent the car from rolling, it is advised that after parking, first put the car in P gear, then pull the handbrake, and finally turn off the car key. 2. Slowly releasing the clutch: After pressing the clutch with your left foot, slowly release it. If the torque transmitted from the engine to the tires gradually increases, and when the clutch is fully released, the phenomenon of rolling will no longer occur. Then, wait until the semi-engagement point is reached, the engine starts to output torque to the tires, and gradually start the car while continuing to release the clutch.
Actually, I've seen quite a few cases of cars rolling on flat ground when parked, and the most critical factor is the parking brake not being engaged properly. Many people think they don't need to pull the handbrake hard on level ground, but if the gear doesn't lock securely, the car can still roll. Once, while repairing a car, I found an old Jetta with parking brake cables so loose you could play a tune on them, yet it still slid on flat ground. Additionally, brake discs contaminated with oil or ice can also cause slipping, especially after washing the car in winter—be extra careful. Some cars left in neutral without the parking brake engaged can slowly roll due to engine vibrations moving the tires, shifting position bit by bit like ants moving house. It's best to develop the habit of a three-step process: press the foot brake - shift to P - engage the parking brake, especially for automatic transmission cars—don't cut corners by just shifting to P.
