Figure 8-44.How weights should be placed when balancing
Figure 8-45.Bubble balancer.
assembly. The wheel assembly must be removed from
the vehicle and placed on the balancer. An indicating
bubble on the machine is used to locate the heavy area of
the assembly. Wheel weights are added to the assembly
until the bubble CENTERS on the crosshairs of the
OFF-THE-VEHICLE BALANCER (spin
balancer) can statically and dynamically balance a
wheel assembly. The wheel assembly is removed from
the vehicle and mounted on the balancer. The assembly
is then spun at a high rate of speed. The machine detects
any vibration of the assembly and indicates where the
wheel weights are to be added. After the weights are
added to the assembly, spin the assembly to again check
ON-THE-VEHICLE BALANCER (spin
balancer) (fig. 8-46) is also used to balance a tire
statically and dynamically. An electric motor is used to
spin the wheel assembly and either a electronic pick-up
unit or hand-operated device is used to determine the
location for the wheel weights. An on-the-vehicle type
balancer is desirable because it can balance not only the
wheel assembly, but the wheel cover, brake disc or
drum, and lug nuts. Everything is rotated as a unit.
Wheel bearings are normally filled with grease. If
this grease dries out, the bearing will fail. Some wheel
bearings can be disassembled and packed (filled) with
grease, while others are sealed units that require
replacement when worn. When performing tire-related
service, check the wheel bearings for play and wear.
For procedures on checking, removing,
and replacing wheel bearings, refer to the
manufacturers service manual.
Tire problems usually show up as vibrations,
abnormal wear patterns, abnormal noises, steering
wheel pull, and other similar symptoms. In some cases,
you may need to operate the vehicle to verify the
problem. Make sure that symptoms are NOT being
caused by steering, suspension, or front-wheel
Figure 8-46.On-the-vehicle balancer.