Measuring Axle and Hub Runout

Theory and Information

• Information

Setup Procedure

• Mounting the dial indicator

Measurements

• Measure

Specifications

• Runout Specifications

Diagnostics

• Diagnostic Action to Take

Theory and Information

When tire and wheel lateral runout occurs on the vehicle and does not occur in off-car testing, the hub or axle flange should be checked.

Setup Procedure

• As shown below, position the dial indicator on the machined surface of the hub, axle flange, or rotor, outside the wheel studs as shown below.

Measurements

• Rotate the hub to find the low spot.
• Set the dial indicator to zero at the low spot.
• Rotate the hub again to check the total amount of runout.

Specifications

Maximum allowed runout is typically 0.005 inch (0.127mm)

Diagnostic Action

• If the runout is excessive with a composite (removable) rotor on the hub, remove the rotor and re-measure the runout on the hub.  If there is a difference, the rotor hub has a problem.  Composite brake rotors can have runout where they contact the hub. Look for rust buildup on the backside of the rotor where the rotor contacts the hub. Clean all rust buildup off or replace the rotor.
• If the runout is out of specification, replace the affected component(s) and re-measure the runout.  If the runout is within the specifications, road test the vehicle.
• If the vibration concern has been corrected, return the vehicle to the customer.
• If the vibration concern is still present on the road test, click here to learn about tire sidewall problems.

This page was last modified Thursday, March 05, 2009 09:02:10 PM

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