Professional Tool And Equipment News - May 2020 - 33

If you suspect a tire is the cause of the
pull, you could try to rotate the tires or
use a tool like the Road Force Balancer
from Hunter to see if that takes care of
the issue. This wheel/tire balancer measures lateral force, which indicates the
"pull value" and the direction of pull in
a tire. Understanding any imbalances in
tire construction and compensating by
either placing weights in precisely the
correct spot or matching tires in place
on the vehicle where laterally pulling
forces oppose each other can eliminate
directional pulls.
Always perform a thorough undercar inspection that includes looking for
worn or damaged steering or suspension
components. It is also a good idea to look
at frame rails or unibody pinch points to
locate any damage or evidence of clamps
used in straightening the frame. If the
vehicle was in a collision, straightening the frame can cause some pulling
problems. Adjustments may need to be
made to the alignment that will allow it
to track straight but are not within the
posted vehicle specifications.
Some common mechanical issues
that go beyond visibly worn components
could include faulty bushings or bearings in strut plates or ball joints that do
not move freely. To check either of these,
use a proper tie rod separation tool, such
as the OTC 315A Tie Rod Separator, to
disconnect a tie rod end. After disconnecting, if one side turns much harder
than the other, it is typically due to the
strut plate bearings or bushing, or faulty
upper or lower ball joint on the side that
turns with more effort.
Brake problems can cause pulls. If
there were no faults detected in the ABS,
the best tool to determine if a brake is
sticking and causing a pull to one side
is a diagnostic thermal imager. I prefer
a thermal imager to an infrared thermometer in these instances because an
imager provides a much clearer picture
of the excess heat caused by a tight
brake. With an infrared thermometer,
you must aim it at the hottest spot in
order to determine the value, and it may

Photo from Hunter Engineering.

not be as accurate.
Keep in mind if the vehicle has been
driven for quite some time when you
are checking the temperature of the
brakes, the temperatures may be somewhat high on both sides of the vehicle. In
those cases, I would suggest that you let
the vehicle cool down for an hour or so.
Make sure temperatures are consistent
on both sides of the vehicle, then drive it
five to ten miles. Use the thermal imager
to check to see if one brake is hotter than
the other. If so, the brake caliper could
be sticking on the hotter wheel, causing
a pull to that side.

ISSUE 2: VEHICLE STEERS LEFT
OR RIGHT AFTER ALIGNMENT

Even after an alignment, some vehicles can veer to one side or the other.
When this occurs, you must check all
the items mentioned in the prior section,
which include looking for worn tires or
steering and suspension components.
Many times, a pull after an alignment is caused by an error on the technicians' part, either in the set-up of the
vehicle or the calibration of the alignment machine. This can be prevented by
training your technicians on the proper
way to use your alignment equipment
and how to prepare the vehicle.

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MAY 2020

p Hunter's RoadForce Elite Balancer

One thing that is easily overlooked
while setting up the vehicle is making
sure that the load within the vehicle
(passenger and trunk compartments)
is correct. If there is an excess load in
the vehicle, the suspension load will not
be appropriate for the alignment specification. In essence, a loaded vehicle
can change the ride height, which can
change the geometry of the suspension
and affect where the caster or camber
must be adjusted to eliminate a pull. I
have heard of large drivers having an
issue with a vehicle pulling, but smaller
drivers not experiencing the problem. In
these instances, try aligning the vehicle
with someone in the vehicle.
Use your vehicle information database to make sure the vehicle is both
prepared properly for the alignment
and the OEM specifications in the alignment machine specifications agree. In
some cases, the data available in the
information source will provide different tire size options. The vehicle repair
information database will also include
information about the calibrations, or
resets, you will need to perform. Also
noted are the tools and procedures
required to perform the resets.

PROFESSIONAL TOOL & EQUIPMENT NEWS

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Professional Tool And Equipment News - May 2020

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