Information on Bushings
There are many different types and locations of bushings just as there are many different methods of checking for worn or deteriorated bushings. Some methods are cumbersome and can take time to position the vehicle correctly in order to inspect many bushings.
If a noise or adverse handling characteristic is noticed while road testing the vehicle, a more comprehensive bushing inspection is warranted. The requirement for Pa. Safety Inspection is a maximum of .250 inch. (1/4 inch) movement with the service brakes applied to eliminate all wheel bearing movement, the vehicle raised, and the wheels in a straight ahead position.
Attempt to move the front wheels laterally without moving the steering gear. If movement is detected, a gauge suitable to measure the steering or suspension play must be utilized. In some instances it is necessary to raise the vehicle under the frame to inspect bushings while other vehicles require a “Dry Park” test in order to determine worn bushings. Some inspectors choose to use a pry bar to determine a worn bushing. If a control arm springs back into position after being pried, the bushing should be acceptable. If the control arm remains in the pried position, the bushing is typically worn and needs to be more carefully inspected.
Bushings can be weather checked as a result of road chemicals or being subjected to lubricants but are not deteriorated to the degree of requiring replacement. A technician should look for inner sleeves to be centered in the rubber cushion or the cushion being broken away from the inner or outer sleeve.
When bushings can be visually inspected, the following could lead to excessive lateral movement: bushing inner sleeves loose or broken from the rubber mount, bushings with breaks from the outer to the inner sleeve, or bushings with missing rubber insulators.
Bushings may need to be replaced and deterioration should be noted on the work order and brought to the customer’s attention.
Bushing Issues that May Impact Measured Movement
LOWER CONTROL ARM BUSHING – Inner bushing sleeve has broken away from the rubber cushion and the rubber cushion is torn or broken which can be observed during a visual inspection. The control arm most likely made a noise on rough roads during a road test.
WORN BUSHING – Rubber cushion has deteriorated to permit inner sleeve to move to one extreme side of the bushing casing. Rubber cushion also exhibits torn or broken condition as well as weather checking.
DETERIORATED AND BROKEN CUSHION – The cushion is weather checked which would not be rejectable but the cushion is also torn or broken from the outside casing into the inner sleeve.
Courtesy of Pennsylvania Automotive Association