Careful pre-alignment practices speed up diagnosis and help minimize comebacks, wheel service specialists said. Stiff price competition on wheel alignments forces many technicians to rush the job, skipping critical setup procedures or overlooking valuable diagnostic clues to suspension and steering problems. Set up job correctly
Compared to some service tasks, setting up for a wheel alignment usually isn't very difficult. But alignment experts said hurried or careless technicians often make the following procedural mistakes that ruin an otherwise-straightforward alignment job. Watch that you don't repeat the same mistakes:
Overlooking a bent wheel. Get in the habit of spinning each wheel with your hand and watching for excessive runout before you mount an alignment head. When in doubt, always measure runout with a dial indicator and compare the reading to manufacturer's specifications.
Ordinarily, a bent wheel causes a vehicle speed-sensitive shimmy or vibration. But some technicians or service advisers don't routinely road test a vehicle before it goes on the alignment rack. Or the service writer who interviews the customer and/or road tests his car doesn't communicate effectively with the alignment technician.
To make matters worse, some techs pay little attention to wheel runout because they claim they see very few bent wheels.
This combination of mistakes leads to a wasted alignment job and a needless comeback for the original complaint.
Skipping the runout compensation step. Some techs actually get away with this shortcut some of the time, but not all the time. The most precisely made wheels and wheel bearing assemblies aren't absolutely perfect, so don't disregard this procedure.
Failing to maintain alignment equipment correctly. Have aligner calibration checked at least as often as the equipment manufacturer recommends. In tire dealerships and service shops where alignment is a staple on the service menu, the most cost-effective approach is keeping the calibration process in-house. To do this, purchase the necessary training and calibration fixtures.
Tire wear patterns that don't agree with actual alignment readings may mean it's time to recalibrate the aligner. But first, see if the tires have been rotated recently.
Another reason tire wear patterns and alignment readings may not agree is vehicle usage. Today, many cars are dual-purpose vehicles but customers seldom clarify ``normal'' usage to service personnel.
A tow hitch on the rear of the vehicle is an obvious clue to dual usages. But more often than not, the salesman who normally hauls several hundred pounds of sales samples in the trunk leaves an unladen car for an alignment appointment. Also, a customer who carpools daily with five large adults may not realize this impacts wheel alignment and tire life, so he doesn't mention it to the service writer.
On the equipment, always keep turnplates clean and lubricated per the manufacturer's recommendation. Often the alignment rack or wheel alignment bay doubles as a suspension service area, so it's not uncommon for road dirt and other debris to accumulate inside some turnplates, preventing themfrom moving freely, leading to erratic or inconsistent alignment readings.
In the worst case, a sticking or uncentered turnplate can upset alignment accuracy or cause suspension misdiagnosis by holding the vehicle at an abnormally high ride height.
Before starting an alignment job, routinely jounce the suspension and verify there's some lateral movement left in the turnplates. If there's no side movement left in the turnplates, double check that each turnplate is centered under the tire. If they are centered, check for debris inside the turnplates.
Inconsistent or grossly inaccurate turning radius (also called toe-out on turns) readings also may indicate sticking or worn-out turnplates.
Another clue to such problems are turnplates that indicate zero when you start the alignment but no longer read zero with the wheels pointed straight ahead when checking toe-out on turns.
If you use magnetic-base alignment heads, always check the base or hub for metal debris before mounting the head on the vehicle. Don't leave the heads on the floor where the magnets can attract metal debris.
Working with uneven turnplate heights. When alignment volume is unusually heavy, some tire dealers do additional alignment jobs on portable turnplate stands in multi-purpose service bays. To ensure an accurate alignment, be sure the heights of the stands are all the same or within the limits set by the equipment manufacturer.
Ignoring tire pressure. Always check and correct tire pressure first. Incorrect tire pressure affects tire life, ride and handling and can cause tire squeal on turns. As little as a 10-psi difference in air pressure from side to side can alter camber one-half degree. Furthermore, a side-to-side difference in tire pressure can cause a pull.
Forgetting to check ride height. Checking ride height is not difficult. At least one manufacturer, Moog Automotive, offers a simple gauge that makes the task even easier.
Although changes in ride height affect all alignment angles, some suspensions are more vulnerable to altered ride height than others.
Correcting ride height means doing the job right the first time instead of apologizing for alignment upon realignment that doesn't solve tire wear, ride or handling problems.
What's more, ride height repairs translate into additional, legitimate suspension service sales. Where needed, recommend higher-capacity, variable-rate replacement springs for dual-purpose vehicles.
Watch for special pre-alignment setup requirements on vehicles equipped with electronic ride-leveling systems or air spring suspensions.