Firebird V8-305 5.0L (1982)
Idler Arm: Testing and Inspection
Checking Idler Movement
1.
Raise the vehicle in such a manner as to allow the front wheels to rotate freely and the steering mechanism freedom to turn. Position the wheels in
the straight ahead position.
2.
As near the relay rod end of the idler arm as possible, exert a 25 pound (110 Newton) force upward and then downward while noticing the total
distance the end of the arm moves. This distance should not exceed a total acceptable movement of 1/8 inch. It is necessary to ensure that the
correct lead is applied to the arm since it will move more when higher loads are applied. It is also necessary that a scale or ruler be rested against
the frame and used to determine the amount of movement because the actual movement can be overestimated when a scale is not used. The idler
arm should always be replaced if it fails this test.
Jerking the right wheel and tire assembly back and forth, thus causing an up and down movement of the idler arm, is not an acceptable method of
checking because there is no control on the amount of force being applied. Caution should be used in assuming shimmy complaints are caused by loose
idler arms. Before suspecting suspension or steering components, technicians should consider shimmy excitation factors, such as dynamic imbalance,
runout or force variation of wheel and tire assemblies and road surface irregularities.
