What Causes Rear Wheel Lockup?
2 Answers
Wheel lockup can be caused by: water ingress into the brake drum, hard emergency braking, sticking of the master cylinder piston cup, or failure to return to position. Below are the specific details: 1. Water ingress into the brake drum causing rear wheel lockup: If the vehicle is parked for too long, moisture is not promptly removed after rain, or the brake drum is not treated after washing, rust can form on the brake drum, eliminating the gap between the drum and brake shoes, leading to wheel lockup. 2. Hard emergency braking causing rear wheel lockup: During emergency braking, if the brake pedal is pressed too hard, the brake shoes can lock the wheels, meaning the brake locks the tires. If the rear axle locks up, it may cause the rear wheels to skid.
I remember once during a long-distance drive, the rear wheels suddenly locked up, which almost caused an accident. After checking, the reason was that the brake caliper had rusted, preventing the piston from retracting—this is quite common, especially in older cars or humid environments. It could also be due to a stuck handbrake cable or blocked brake lines causing brake fluid obstruction. Don’t underestimate this issue—it can range from minor brake noise to severe skidding or loss of control, which is extremely dangerous. It’s best to maintain the brake system regularly, checking for pad wear and fluid degradation. I recommend new car owners pay close attention to their vehicle’s condition. If the brakes feel off, take it to a 4S shop or professional repair center for a thorough inspection—don’t try to tough it out to save money. Safety comes first, and it’s also important to develop good driving habits, like avoiding excessive hard braking.
