Some specialists will adjust just the front wheels, but most will not. All cars today get a "four-wheel-alignment" even when the rear wheels are not adjustable. That's because the computer looks at the direction the rear wheels are steering, then has the mechanic set the front wheels to match them to insure the steering wheel is straight. If a rear wheel is allowed to turn a little due to a worn part, it is going to affect the steering wheel position.
That changing steering wheel position is going to be minimal and probably not noticeable, but there's two things the mechanics and shop owners are worried about. The first is once the front wheels are aligned, you aren't going to notice a problem with handling or steering control, so you won't come back to have the work done on the rear. That leaves you out there with a false sense of security, less-than-perfect tire wear, and less-than-perfect handling. Performing just half the alignment means they're putting their stamp of approval on your car that it is safe to drive.
The second problem is if you're in a crash after the other guy runs a red light, his lawyer or insurance investigator is going to find the worn part along with any other worn parts or modifications to your car that affect handling, braking, and steering response. They will use that to convince a jury that you were partly at fault for the crash because you were less able to avoid it, and they might be right. At this point the shop that did half the job becomes a party to that lawsuit. It's that threat of lawsuits that are on the minds of all mechanics and shop owners every time they work on a car. They can even be taken to task for a defect on a car that has nothing to do with what is was in the shop for. If they don't point the problem out to you, they can be held liable in some states if it causes a problem later. If they do point out the defect, they run the risk of being accused of trying to sell you parts or services you don't think is needed.
While those problems sound serious, the more general concern is they're taking your money for an alignment, and in return you expect the car to go straight, corner smoothly and predictably, and it should have good, even tire wear. Those expectations can not be met when a worn suspension or steering part is on the car, therefore, they're taking your money for a service they know they can't deliver. It's the less-than-reputable shop that will gladly do the alignment on your car with a worn part.
Monday, May 13th, 2019 AT 7:09 PM