It starts out as a small oily smudge on the outside of the brake's backing plate. You notice it, but ignore it. Next time you look, there's oil and absorbed dirt making a mess all around the wheel.

A slow-leaking tire undoubtedly ranks among the more frustrating problems you might encounter as a car owner, as it not only trips your car's TPMS (Tire Pressure Monitoring System) on the regular, but ...