Pinpoint Test J: Wheel And Tire

NOTE: Wheel or tire vibrations felt in the steering wheel are most likely related to the front wheel or tire. Vibration felt through the seat are most likely related to the rear wheel or tire. This may not always be true, but it can help to isolate the problem to the front or rear of the vehicle.
• Test drive the vehicle at different speed ranges.
• During the road test, if the vibration can be eliminated by placing the vehicle in NEUTRAL or is affected by the speed of the engine, the cause is not the wheels or tires.
• Is there a vibration and noise? 

Yes  : GO to J2.

No  : The wheel and tires are OK. CONDUCT a diagnosis on other suspect systems.

WARNING: The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.
WARNING: If equipped with fire suppression system, depower the system. For important safety warnings and procedures, refer to FIRE SUPPRESSION SYSTEM .
• With the vehicle in NEUTRAL, position it on a hoist. Refer to JACKING & LIFTING .
• Check the front wheel bearings. Refer to WHEEL BEARING CHECK .
• Are the wheel bearings OK? 

Yes  : GO to J3.

No  : INSPECT the wheel bearings. ADJUST or REPAIR as necessary. TEST the system for normal operation. If equipped with fire suppression system, GO to  J11.

• Check the tires for missing weights.
• Check the wheels for damage.
• Inspect the tire wear pattern. Refer to the TIRE WEAR PATTERNS CHART .
• Do the tires have an abnormal wear pattern? 

Yes  : CORRECT the condition that caused the abnormal wear. INSTALL new tire(s). TEST the system for normal operation. If equipped with fire suppression system, GO to  J11.

No  : GO to J4.

• Spin the tires slowly and watch for signs of lateral runout.
  Fig 1: Identifying Sings Of Lateral Runout

  Courtesy of FORD MOTOR CO.
• Spin the tires slowly and watch for signs of radial runout.
  Fig 2: Identifying Sings Of Radial Runout

  Courtesy of FORD MOTOR CO.
• Are there signs of visual runout? 

Yes  : GO to J5.

No  : CHECK the wheel and tire balance. CORRECT as necessary. TEST the system for normal operation. If equipped with fire suppression system, GO to  J11.

• Measure the radial runout of the wheel and tire assembly. A typical specification for total radial runout is 0.045 inch.
  Fig 3: Measuring Radial Runout Of Wheel And Tire Assembly

  Courtesy of FORD MOTOR CO.
• Is the radial runout within specifications? 

Yes  : GO to  J8.

No  : GO to J6.

• Measure the radial runout of the wheel. A typical specification for total radial runout is 0.045 inch.
• Is the radial runout within specifications? 

Yes  : INSTALL a new tire. TEST the system for normal operation. If equipped with fire suppression system, GO to  J11.

No  : GO to J7.

• Measure the pilot or bolt circle runout. A typical specification for radial runout is:
  • pilot runout- less than 0.15 mm (0.006 inch).
  • bolt circle runout- less than 0.38 mm (0.015 inch).
• Is the radial runout within specifications? 

Yes  : INSTALL a new wheel. TEST the system for normal operation. If equipped with fire suppression system, GO to  J11.

No  : REPAIR or INSTALL new components as necessary. REFER to FRONT SUSPENSION for the front wheels or REAR SUSPENSION for the rear wheels. If equipped with fire suppression system, GO to  J11.

• Measure the lateral runout of the wheel and tire assembly. A typical specification for total lateral runout is 1.14 mm (0.045 inch).
  Fig 4: Measuring Lateral Runout Of Wheel And Tire Assembly

  Courtesy of FORD MOTOR CO.
• Is the lateral runout within specifications? 

Yes  : Wheel and tires OK. CONDUCT diagnosis on other suspect systems. If equipped with fire suppression system, GO to  J11.

No  : GO to J9.

• Measure the lateral runout of the wheel. A typical specification for total radial runout is 1.14mm (0.045 inch.
• Is the lateral runout within specifications? 

Yes  : INSTALL a new tire. TEST the system for normal operation. If equipped with fire suppression system, GO to  J11.

No  : GO to J10.

• Measure the flange face lateral runout. A typical specification for lateral runout is:
  • hub/brake disc - less than 0.13 mm (0.005 inch).
  • axle shaft - less than 0.25 mm (0.010 inch).
• Is the lateral runout within specifications? 

Yes  : INSTALL a new wheel. TEST the system for normal operation. If equipped with fire suppression system, GO to J11.

No  : REPAIR or INSTALL new components as necessary. REFER to FRONT SUSPENSION for the front wheels or REAR SUSPENSION for the rear wheels. If equipped with fire suppression system, GO to J11.

• Verify that the fire suppression system is repowered. For additional information, refer to FIRE SUPPRESSION SYSTEM .
• If the fire suppression system repowered? 

Yes  : Fire suppression system repowering is complete.

No  : REFER to FIRE SUPPRESSION SYSTEM for fire suppression system depowering and repowering procedure.