Why Does My Car Pull to the Right When Driving?by Richard Rowe
Once upon a time, cars were engineered with a very slight pull to the right. The idea was that if the driver fell asleep at the wheel, the car would drift off the road instead of into oncoming traffic. Even today, long since that practice ended, it's not uncommon for the "crown" or rise in the middle of the road to cause a certain degree of lateral drift. But there may come a time when you must eventually acknowledge that yes indeed, this thing is definitely trying to drive itself into the trees.
Bad front suspension alignment is probably the No. 1 cause of a car pulling to one side or the other. Almost any kind of alignment problem can cause this, especially if it only affects one wheel. The adjustable steering tie rod that links your front wheels together, and to the steering box, is a likely suspect, especially on rack-and-pinion steering systems. These systems typically have separate adjustments for the "toe angle," the inward or outward wheel angle, for the left and right sides. If one side is adjusted out a little further than the other, the car will pull in that direction. However, camber and caster settings out of spec are just as capable of causing a pull to one side.
Any broken or worn-out part in your suspension may throw it out of alignment and cause a pull in one direction. Usually this will result in a pull that gets more severe with speed, though it's not impossible for certain kinds of failures to cause a low-speed pull that lightens up as the caster angle of the wheel straightens it out at speed. Steering end-link failures and bent or broken tie rods -- or the bushings in them -- might cause this kind of behavior in some cases. Otherwise, you could be looking at a bent or broken control arm, worn-out or shredded control arm bushings, a broken or loose strut or strut mount; effectively, anything in the suspension that moves. A failure in the steering rack's hydraulic power assist circuit is also possible, but not as likely.
A wheel encountering resistance will drag one side of your vehicle back like an anchor dragging on the ground, causing it to pull to that side. Stuck brake slave cylinders and disc brake caliper sliders are notorious for this, causing the brake caliper on one wheel to constantly rub against the disc instead of disengage as it should when you take your foot off the pedal. There are two classic symptoms here. The first is a brake disc or drum on one side that's scorching hot after you drive for a few minutes in a perfectly straight line. The second is that the vehicle straightens out, or the pull drastically decreases in strength, when you hit the brakes. It's not impossible for a bad antilock brake modulator to cause this kind of brake drag, though it's a lot less likely than a bad caliper piston or stuck slider.
A very bad wheel bearing can cause a pull to one side, not just because of wheel drag, but because it can throw the wheel out of alignment. However, you'll almost certainly hear the bearing grumbling and grinding, and notice the steering wheel vibrating or shimmying, long before the bearing causes a pull. Some vehicles will developing pulling problems after the installation of aftermarket performance lowering springs; sometimes this has to do with camber changes as a result of the lowering, but just as often it's due to a mistake during installation, like loose fasteners or missing alignment shims. Tire failures are always a possibility, but should become evident when you rotate your tires. If the pull goes away or changes when you rotate your tires, then odds are good that the tire you took off the right-front of the vehicle is bad. But before anything else, check your tire pressure on that wheel; low tire pressure will cause excess wheel drag, and a pull in that direction.
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.