Why is there a burnt smell from the rear wheel and the hub is very hot?
2 Answers
The reasons for a burnt smell from the rear wheel and the hub being very hot include worn wheel hub bearings, lack of lubrication in the bearings, and abnormal brake caliper return. The specific reasons are as follows: Worn wheel hub bearings: If the wheel hub bearings are assembled too tightly or abnormally worn, it can cause the car's wheel hub to become hot, and in severe cases, it may even burn out the bearings. Lack of lubrication in the bearings: If the temperature is too high, the grease inside the bearings will melt and flow out, affecting the braking performance and causing the wheel hub to become hot. Abnormal brake caliper return: If the brake caliper does not return properly, it can cause the brake pads to lock, keeping the brake pads and brake disc in a state of constant friction, leading to brake drag. In such cases, the temperature of the brake drum and wheel hub will also rise.
I've been driving for over a decade, and when the rear wheels get hot with a burning smell, it's most likely a brake issue. I remember encountering this once on a long trip—it turned out the parking brake cable was stuck, causing the brake pads to continuously grind against the rotors. After driving just over ten kilometers, the wheel hubs were hot enough to fry an egg. It could also be due to the brake caliper piston rusting and failing to retract, or the guide pins seizing, keeping the brake pads pressed against the rotor. Another possibility is a lack of lubrication or damage to the wheel bearing, which causes temperatures to spike, often accompanied by a noticeable humming noise. If the tire is rubbing against the fender liner or suspension components, you might also detect a burning odor, though usually, the tire will show visible wear marks first. If you experience this, don't push your luck—pull over immediately to let the wheels cool down. Otherwise, if the brake fluid boils, you'll be in real trouble.
