CLEANING AND INSPECTION CONTINUED
Servicing and Adjusting Fan Drive Idler Gear and Hydraulic Pump Idler Gear Roller Bearings
The tapered roller bearings and spacer are furnished as a matched unit, so a definite
procedure for adjustment of tapered roller bearings, due to normal wear, must be followed.
1. Assemble complete bearing assembly (Figure 10, Item 2) on a flat surface (surface plate).
2. Place a minimum 20 lb (9 kg) weight (Figure 10, Item 1) on top of bearing assembly (Figure 10, Item 2) as
shown in Figure 10. This will keep rollers in alignment.
Be sure to place lower parallel or spacer under bearing, and then rest weight on top of
upper parallel or spacer. This is done to keep weight concentrated on bearing cone. Both
upper parallel or spacer and lower parallel or spacer must be of equal thickness.
3. Rotate cup (Figure 10, Item 3) a minimum of four revolutions in each direction.
4. With spacer (Figure 10, Item 6) in place, set dial indicator at zero. Check at three different points.
5. Slide dial indicator off cone (Figure 10, Item 7) carefully. (Do not upset dial indicator setting.)
6. Remove weight (Figure 10, Item 1), parallels (Figure 10, Items 8 and 5), upper cone (Figure 10, Item 7), and
spacer (Figure 10, Item 6). Then reinstall parallels and weight. Do not reinstall spacer.
7. Repeat rotation of cup (Figure 10, Item 3) and slide dial indicator on cone (Figure 10, Item 7). Record accurate
reading from dial indicator. Check at three different points.
A bearing assembly that is heavily pitted or scored must NOT be salvaged.
8. The factory end play specification in a new bearing assembly is 0.009 to 0.012 in (0.23 to 0.30 mm) for idler
shaft bearing or 0.009 to 0.011 in. (0.23 to 0.28 mm) for hydraulic pump idler gear bearing. If reading on dial
indicator shows a greater drop than maximum factory set end plate, grinding or lapping of spacer (Figure 106)
is necessary. The amount to be ground off of spacer is the difference between indicator reading and factory set
end play (0.009 to 0.012 in. [0.23 to 0.30 mm]).
Figure 10. Adjustment of Tapered Roller Bearings.