* Brake caliper seizure: This is a very common cause. The caliper piston may be stuck, preventing the brake pads from releasing. This can be due to corrosion, damage, or a build-up of debris.
* Sticking brake pads: Similar to a seized caliper, the brake pads themselves might be sticking in the caliper, preventing them from retracting properly. This can be due to corrosion, damage, or the build-up of brake dust and debris.
* Hydraulic system issues: A problem within the hydraulic brake system could lead to higher pressure at the right rear wheel than others. This could include a blockage in the brake line, a leaking wheel cylinder (if it's a drum brake system), or a faulty proportioning valve (which controls pressure distribution between front and rear brakes).
* Parking brake cable: If the parking brake cable is sticking or binding, it could keep the right rear brake engaged, even when the regular brake pedal is released.
* Wheel cylinder issues (Drum brakes): In vehicles with drum brakes, a faulty wheel cylinder can cause the brakes to lock. The wheel cylinder pushes the brake shoes outwards, and a leak or internal malfunction can prevent them from returning to their resting position.
* Low brake fluid: While unlikely to cause *just* the rear right to lock, critically low brake fluid can cause uneven braking force distribution and potentially lead to this symptom.
Troubleshooting Steps (Do NOT attempt brake repair without proper mechanical knowledge and safety precautions):
1. Check the parking brake: Make sure the parking brake is fully released.
2. Inspect the brake caliper: Look for signs of damage, corrosion, or sticking. Try to manually move the caliper piston (safely and cautiously).
3. Check the brake fluid level: Low fluid could indicate a leak somewhere in the system.
4. Feel the wheel: After driving, touch the wheel rim. If it’s significantly hotter than other wheels, it suggests excessive braking at that point.
Important Note: If your right rear brake is locking up, it's a serious safety hazard. Do not drive the vehicle until the problem is diagnosed and repaired by a qualified mechanic. Driving with a locked brake can lead to accidents, especially at higher speeds.
