Important: 
   •  Do not jerk the right tire and wheel assembly back and forth,
causing an up-and-down movement of the idler arm. This is not an acceptable
 testing procedure because there is no control on the amount of force being
 applied to the idler arm.    •  Use care whenever loose idler arms are suspected of causing shimmy
complaints. Before suspecting suspension or steering components, consider
 the following areas:       -  Dynamic imbalance       -  Runout       -  Force variation of tire and wheel assemblies       -  Road surface irregularities 
The allowable deflection is 3.18 mm (1/8 in) from the center for a total of 6.35 mm (¼ in) (1).