If your vehicle is showing car pulls to the left or right while driving straight, here are the most likely causes and the parts you'll need to fix each one.
Significantly lower air pressure in one tire creates drag on that side of the vehicle. Alternatively, a defective internal belt in the tire (radial pull) can cause the vehicle to pull even if pressures are correct.
Hitting potholes, curbs, or failing to perform an alignment after replacing suspension components can knock the wheels out of parallel (camber, caster, or toe), causing the vehicle to drift.
A seized brake caliper piston, stuck slide pins, or a collapsed brake hose can apply constant braking force to one wheel, dragging the car to that side. This is often accompanied by a burning smell or excessive brake dust.
Worn tie rods, ball joints, or control arm bushings allow the wheel to shift under load. This changes the alignment dynamically while driving, leading to wandering or pulling.
A severely worn wheel bearing can create excessive friction and looseness on one side of the axle, leading to a pull. This is usually accompanied by a loud humming or grinding noise that changes pitch when turning.
Internal leaks in a hydraulic steering rack or a failing electric power steering motor/sensor can apply uneven assist, actively pulling the steering wheel to one side without driver input.