KINETIC BALANCING  (UP & DOWN VIBRATIONS)  OF FRONT WHEELS ON TRUCKS

1. Place the jack under the center of the axle and raise both front wheels approximately 3 inches.
   
2. Remove all weights from inside and outside of the rim. Remove all stones from tire tread. Point wheels straight ahead.
   
3. Wheel should revolve freely. Tap brake backing plate with weight pliers to free wheel if necessary.
   
4. Position pick-up under the front axle. Adjust pick-up arm length until magnet contacts clean, flat surface under axle as close to wheel as possible (see Figure 1).
   
   See Figure 1 for pick-up positioning and adjustment for either high or low axles.
   
   NOTE: If the pick-up magnet is not positioned properly or is not making good contact, wrong meter reading will result, or meter needle will vibrate excessively.
   
5. Check for radial runout. Position balancer so that spinner will contact tire tread squarely when balancer is rolled forward toward wheel. Depress brake lever. Roll balancer forward until the brake shroud is 1/4″ from the tire tread. See Figure 2.
   
   Rotate the tire by hand and watch clearance between the brake shroud and the tire tread.
   
   If more than 1/4″ movement is noted, check for bent rim, bad wheel bearing, tire bead improperly seated, or flat spot on tire. If the condition is not corrected before balancing the wheel, it may cause unsatisfactory results.
   

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FIG. 1 POSITION PICK-UP FOR HIGH OR LOW AXLE

FIG. 2 CHECK RADIAL RUNOUT