* Caliper Piston Seized: This is the most common cause. The piston inside the brake caliper might be seized due to corrosion, rust, or the buildup of debris. This prevents it from retracting fully, keeping the brake pads pressed against the rotor, even when you're not braking. You'll likely notice the wheel is unusually hot after driving.
* Caliper Slide Pins Stuck: The caliper slides along pins that allow it to move in and out as it compresses the brake pads. If these pins are seized due to corrosion or rust, the caliper can't move freely, leading to the pads constantly contacting the rotor.
* Brake Hose Restricted: A kinked, damaged, or internally restricted brake hose can prevent proper pressure release from the caliper, causing the brakes to stick. This is less likely to cause *only* the driver's side front to stick, but it's possible if the hose is particularly damaged in that specific area.
* Brake Pad Issues (Less Likely): While less likely to cause constant sticking, a brake pad that's severely worn or damaged *could* potentially interfere with the caliper's movement, contributing to the problem.
* Master Cylinder Issue (Least Likely): A problem with the master cylinder is less likely to cause only one wheel to stick. However, a faulty master cylinder could contribute if it's not properly releasing pressure.
What to do:
This is a serious safety issue. Driving with a sticking brake can cause damage to the brake system, overheating, and loss of control. Do not drive the car until the problem is fixed.
You should have a mechanic diagnose the problem. However, you can perform a preliminary check yourself (but remember, safety first!):
1. Check the temperature of the front driver's side wheel: After a short drive, carefully feel the wheel. If it's significantly hotter than the other wheels, this strongly suggests a sticking brake.
2. Visually inspect the caliper: Look for signs of rust, corrosion, or damage on the caliper and its slide pins. You might be able to see if the piston is sticking out.
3. Try to manually move the caliper: (Use caution!) With the wheel removed, see if you can gently move the caliper back and forth. If it's stuck, that confirms the issue is with the caliper itself or its associated components.
In short: The most probable culprit is a seized caliper piston or stuck caliper slide pins. Get it checked by a mechanic as soon as possible. Continuing to drive with a sticking brake is dangerous.
