What follows are some simple steps for aligning
vehicles to ensure that you do the job right the first time.
- Tip No. 1: Don’t neglect the importance of the prealignment
inspection.
The more thorough the prealignment inspection, the better your
chances are of not overlooking something that might cause a comeback
after the wheels have been aligned.
For starters, ride height should always be measured at all four
corners of the vehicle, not just eyeballed. An inch or more of
sag may not be apparent, but it can cause noticeable alignment
problems. If you find weak springs, recommend replacing them.
Replacement is a better choice than shimming because it restores
the feel of the original springs, as well as ride height.
Another dimension to measure is the wheelbase on both sides, as
well as crosswise; this is a simple and easy way to detect chassis
distortion. If the wheels aren’t square to the chassis, the vehicle
won’t drive straight.
Check the front and rear tires for signs of unusual wear. Camber
wear on the front may indicate worn or damaged parts. Toe wear
on the front can indicate worn or damaged parts, or it could be
caused by misalignment in the rear. Rear toe or camber wear on
cars with independent rear suspensions may also be a clue to worn
or damaged parts.
Also, check and adjust the inflation pressure in each tire before
doing the alignment. The amount of air in the tires affects ride
height, so it needs to be right before proceeding with the job.
A low tire can also cause a steering lead to one side, not to
mention accelerated tire wear and overheating of the tire.
Another step that’s often overlooked or skipped is making sure
all four tires are the same size and have the same basic tread
pattern. A difference in tire sizes side to side or front to rear
will alter ride height and alignment readings. A smaller tire
at one location can also create a steering pull (usually toward
the side with the smaller tire if the smaller tire is up front).
A difference in tread widths and tread patterns (conventional
tread versus all-season tread, for example) side to side may create
a steering pull, too.
Also inspect the wheels. Many vehicles have alloy wheels that
may have cracks or other damage that would call for replacement.
You should also spin each wheel by hand to check for brake drag.
Finally, check the condition of all steering and suspension components
for wear. In addition to inspecting the tie-rod ends, ball joints,
control-arm bushings, shocks and struts (including the condition
of the upper strut mounts), you should take the time to check
the wheel bearings for excessive play or roughness, the condition
of the rack mounts (if equipped with rack-and-pinion steering),
the rear control-arm bushings, sway-bar links, motor mounts and
steering-column joints. Saab 900s, for example, have two universal
joints in the steering column that tend to rust and create a hard-steer
condition.
- Tip No. 2: Check the accuracy of your alignment equipment.
A simple but often overlooked cause of comebacks is alignment
equipment that’s out of calibration. The cause may be something
as simple as a rack that isn’t level or alignment heads that are
out of adjustment – or something as serious as a mechanical or
electronic glitch that produces inaccurate measurements. If you
suspect a problem, contact your equipment representative for help.
If you suspect your alignment equipment has seen better days,
invest in new equipment.
- Tip No. 3: Do a complete alignment.
Time is money, so the faster you get the job done the more money
you make, right? Wrong. If you don’t do a good job because you’ve
skipped things like checking toe-out on turns, ride height, SAI,
caster (if nonadjustable), rear-wheel alignment (if nonadjustable),
the condition of steering and suspension parts, etc., you may
end up having to do the job over again.
- Tip No. 4: Don’t try to align worn parts.
To hold an accurate alignment, steering and suspension parts must
be in good condition, which means no more play than allowed by
the vehicle manufacturer. Always refer to a reference manual for
the exact specs since acceptable ball-joint play can vary considerably
from one application to another.
Honda, for example, generally allows up to .020 inches of play
in the lower ball joints on Accords, Civics and Preludes. Nissan,
on the other hand, may allow only .012 inches of play on an older
B210 to as much as .100 inches of play on an ’88 Maxima or Pulsar.
As parts wear, they get progressively looser and are less able
to maintain accurate wheel alignment. If a tie-rod end or ball
joint is borderline, it’s better to replace it now.
Inspect the steering and suspension parts carefully, and replace
any that are worn beyond normal acceptable service limits before
the wheels are aligned. If the customer won’t OK the needed repairs,
refuse the alignment job and send him someplace else.
- Tip No. 5: Don’t just set the toe and let it go.
If a front-wheel-drive car has no factory adjustments for camber
or caster (Honda, for example), don’t just set the toe and let
it go – always read all the angles. Why? Because if there’s a
problem, a simple toe adjustment won’t fix it.
Many so-called "nonadjustable" suspensions can often
be easily adjusted with the help of various kinds of aftermarket
alignment aids. If you’re not already familiar with the use of
camber/caster shims, caster wedges, offset bushings and the like,
get some catalogs from the specialty alignment-product suppliers
and find out what’s available. Better yet, maintain an inventory
of such products so you’ll have them when you need them.
- Tip No. 6: Set to the factory-preferred specs, not rule-of-thumb
specs.
There are no such things as "rule-of-thumb" specs when
it comes to wheel alignment. What works on one vehicle may or
may not work on another. Front-wheel-drive cars usually require
different toe settings than rear-wheel-drive cars. Vehicle weight,
chassis design, chassis loading, tire size, driveline configuration
and intended use all affect wheel-alignment settings that the
vehicle manufacturer develops for the vehicle.
Always use the "preferred" specs rather than the "acceptable
range" because the former is tighter than the latter. If
a spec allows up to plus or minus a degree of camber either way
and the wheel is close to the acceptable limit, the overall difference
in camber side to side may be too great.
Generally speaking, most vehicles handle best when there’s less
than half-degree difference in camber and caster side to side.
One exception is Mazda Navajo trucks. If the vehicle has a steering
drift to the right, Mazda recommends making right caster .050
degrees greater than the left side.
- Tip No. 7: Compensate for how the vehicle is driven and
used.
Vehicle loading can have a very pronounced effect on wheel alignment.
If a vehicle that’s normally loaded with passengers or cargo is
aligned while empty, the tires will likely exhibit rapid wear
because they won’t be running true when the vehicle is driven
while carrying its normal operating load.
Talk to the customer. If Dad car pools or Mom hauls the neighborhood
kids on a regular basis, some extra weight should be added to
the vehicle to simulate the extra load that’s usually carried.
If the vehicle is a minipickup or a sport-utility vehicle that’s
used to haul loads on a frequent basis, have a helper or two hop
in the back to simulate the extra weight when you take your alignment
readings and make your adjustments.
- Tip No. 8: Align all four wheels, not just the ones up
front.
Four-wheel alignment has become much more commonplace in recent
years, but there are still those who won’t align all four wheels
because the customer doesn’t want to pay "extra" for
a four-wheel alignment. This may be more of a marketing problem
than a technical one, but the public needs to be educated that
the rear wheels have just as much influence on where a vehicle
goes as the ones up front. The emphasis should be on performing
four-wheel alignments, not on the cheaper and easier two-wheel
alignments.
On rear-wheel-drive cars and trucks that have no factory provisions
for rear-wheel alignment, the temptation is to align the front
wheels only and forget the rear. But if the axle is cocked and
creates a thrust angle, the steering wheel will be off-center
and the vehicle will lead to one side. The cure? Check the rear
thrust angle and then align the front wheels to it. The vehicle
will still dogtrack slightly, but at least it will steer straight.
On front-wheel-drive vehicles with or without adjustable rear
suspensions, rear toe and camber should always be checked. Rear
tire wear and rear-axle steer can cause major headaches with some
of these vehicles, so checking all four wheels will rule out any
problems that might be overlooked if only the front wheels are
aligned. Some Volkswagen Fox, Golf and Jetta models, for example,
have a problem with rear-tire wear caused by rear-toe misalignment.
- Tip No. 9: Make sure the steering wheel is centered.
One of the leading causes of alignment comebacks is a steering
wheel that’s off-center. Tire wear takes a while to catch up with
a customer if the alignment isn’t on the mark, but an off-center
steering wheel will be noticed immediately.
To avoid this kind of problem:
- Make sure the steering wheel is centered before the wheels
are aligned. - Align all four wheels to eliminate rear-axle steer and thrust
angle (if possible). If not, then align the front wheels to the
rear thrust angle. - Adjust both tie rods equally so toe is centered.
- Test drive the vehicle before it’s returned to make sure the
steering wheel is centered and the vehicle drives straight.
Never – I repeat – never remove and remount the steering
wheel to cover up an off-center steering wheel. If the wheel isn’t
centered, there’s a reason. Find it. Don’t camouflage it.
- Tip No. 10: Test drive the vehicle before it’s returned
to the customer.
A simple test drive can reveal a lot of problems that might have
been otherwise overlooked. Sure, test drives take time, but so
do comebacks. Think of it as a final quality-control check.
Larry Carley is a contributing editor to BodyShop Business.
