What are the reasons for the car sliding forward when the brakes fail?
3 Answers
Insufficient battery or fuel, locked steering wheel, electrical or electronic failures, and fuel system issues can all cause the car to slide forward when the brakes fail. Insufficient car battery or fuel: To check if the battery is low, turn the ignition key to the 'on' position (for push-start models, press the start button twice without pressing the brake). Turn on the headlights; if the light dims significantly or doesn't turn on, and the horn sounds weaker than usual or doesn't sound at all, the battery is likely low. If the fuel gauge shows below the red line, the car won't start either. Locked steering wheel preventing startup: Many cars have a basic anti-theft feature where removing the key without straightening the steering wheel or turning it activates the steering lock. This locks the steering column, preventing the wheel from moving and the car from starting. Electrical or electronic failures: Electrical failures include blown fuses, open high-voltage coils, broken low-voltage circuits, detached central ignition wires, leaking distributor rotors, or damaged spark plugs. Electronic failures mainly refer to malfunctions in the central computer control panel. Fuel system issues: Fuel system problems can occur in the fuel pump failure, clogged fuel lines, blocked fuel filters, carbon buildup on spark plugs, or damaged fuel injectors. If the car slides forward due to brake failure, immediately press the clutch pedal and shift into neutral. This disengages the engine power from the wheels, allowing you to brake normally and slowly pull over to the roadside. Then, turn off the engine and inspect the issue or call for a tow truck.
Yesterday, while helping my neighbor inspect his old car, we encountered this exact situation. The brake pedal felt spongy and the car kept creeping forward, mainly because the brake pads were worn as thin as paper, severely reducing braking power. Upon checking the brake discs, we found deep grooves worn into the edges—in this condition, the pads couldn’t grip the disc surface effectively during hard braking. Another easily overlooked issue was the brake fluid, which hadn’t been changed in two years. With excessive moisture content, bubbles formed during braking, causing the pedal to feel soft. A reminder to everyone: replace brake pads if their thickness falls below 3mm, and it’s best to test the brake fluid’s moisture content annually.
I experienced brake fade last time when going downhill on a mountain road! Continuous braking caused the brake pad temperature to soar to 400-500 degrees, carbonizing the surface material and causing a sharp drop in friction. At this point, you can smell a burnt odor, and the brake pedal may slightly bounce. It's recommended to shift to a lower gear and use engine braking on long descents to give the braking system a break. After returning home, I found the front brake pads covered in blue-purple high-temperature marks, so I replaced the entire set for peace of mind.
