GEAR (91 T.-R.H. AND 91 T.-L.H.) 1L9639 - Caterpillar

Tools Needed: 8S2338 Indicator GroupIf a light, constant brake application at low speed causes a feel of soft regular oscillation that gives a steering effect of several short turns instead of a single, smooth turn, the brake drum is not in correct alignment with the shaft.1. Raise the machine and put blocks under it to hold the track off of the ground.2. Remove the steering clutch covers.3. Start the engine, disengage both steering clutches and hold them in disengaged position.4. Put a block about 8 in. (200 mm) long between clutch yoke (2) and wall of steering clutch case (1). Be sure the block is not in the way of brake linkage.5. Stop the engine.6. Tighten bolts (5) enough to hold drum in place.7. Fasten a dial indicator on the case (1) so it makes contact with brake drum (3).8. Turn brake drum with a bar in track. Read the indicator only when the track is turned with a constant movement. Sudden movements can cause wrong measurements to show on the indicator, because there is radial clearance in the pinion bearings.9. If the indicator shows more than .005 in. (0.13 mm) total runout, loosen the bolts (5) and use a bar to move brake drum a small amount.10. Tighten the bolts, check total runout again, and repeat if needed until total runout is .005 in. (0.13 mm) or less. On some machines, you will need to remove the bolts (5) and turn flange (4) until the next set of holes are in alignment.11. When the drums show acceptable runout, tighten the drum-to-pinion bolts (5) to a torque of 90 to 100 lb.ft. (120 to 135 N m)12. Do Steps 6 through 11 for the other brake drum.