What Causes Rear Wheel Lock-Up in Cars?
2 Answers
Wheel lock-up can be caused by: water ingress in the brake drum, hard emergency braking, sticking of the master cylinder piston cup, failure to return to position, etc. Here are the specific details: 1. Water ingress in the brake drum leading to rear wheel lock-up: If the vehicle is parked for too long, moisture is not promptly removed after rain, or the brake drum is not treated after water ingress during car washing, the brake drum may rust, eliminating the gap with the brake shoe, thus causing wheel lock-up. 2. Hard emergency braking causing rear wheel lock-up: During emergency braking, if the brake pedal is pressed too hard, the brake shoe may lock the wheel, meaning the brake locks the tire, and if the rear axle locks up, it may result in rear wheel skidding.
I've been driving for over 20 years and have encountered rear wheel lock-up many times, mainly due to issues with the braking system. The most common problem is a seized brake caliper, where dirt gets inside or rust forms, causing the piston to stick and the brake to firmly grip the wheel. Hydraulic fluid leakage is also a major issue—when pipes are damaged or fittings loosen, insufficient oil pressure makes the brakes extremely stiff, and the wheels lock up when you press the pedal. Another culprit is a faulty ABS system, which is supposed to prevent lock-up but, if not functioning, makes the rear wheels particularly prone to locking. Additionally, overly worn brake drums or discs can stick to the brake pads, especially after prolonged parking in rainy conditions. These issues can easily lead to dangerous skidding. I recommend checking the brake fluid and replacing components annually; moving the wheels slightly after parking to prevent sticking; and immediately slowing down and pulling over if lock-up occurs—safety comes first.
