A car pulls to the left; which of these could cause the problem?

When a car pulls to one side, it is often related to the alignment of the wheels, specifically caster, camber, and toe angles. Caster refers to the angle of the steering axis in relation to the vertical line when viewed from the side of the vehicle. Negative caster means that the top of the steering axis tilts towards the front of the vehicle. If the left front wheel has too much negative caster, it can cause handling issues that may lead the car to pull to the left. This misalignment affects the directional stability and how well the wheels track together, contributing to the problem you're observing.

In contrast, while factors like under-inflation in tires or weaknesses in the suspension may influence handling, they typically don’t create a consistent lateral pull in the same manner as incorrect caster angles do. For example, an under-inflated right rear tire may lead to uneven tire wear or handling issues but isn't likely to directly cause the vehicle to pull to the left in a straightforward manner. Similarly, an over-inflated left front tire can affect steering response but won't inherently cause a directional pull unless paired with other significant issues. Worn shock absorbers may affect ride comfort and the overall handling of the vehicle but are less likely to produce