RING-RETAINING 7T8639 - Caterpillar

Introduction
This instruction provides the necessary procedure for installing carrier rollers on D6H Tractors, including those that have the extended roller frame (seven track rollers).The addition of the carrier rollers will aid in maintaining proper track sag under a variety of conditions. In addition, track slap and noise will be reduced by smoothing out the upper side track travel.Reference: Service Manual and Parts Book.Necessary Parts
Installing Carrier Roller
1. Loosen the track adjustment mechanism before starting the carrier roller installation procedure. Refer to the Service Manual for the proper procedure.2. Raise the track with an overhead crane or other lifting device with adequate capacity high enough so link rails are at least 330 mm (13.0 in) above the track roller frame where the carrier roller will be located.Place a wooden block between the track roller frame and the link rails (outside the carrier roller area) to help support the track.Also, leave the overhead crane or other lifting device in place. 3. Measure 376 mm (14.8 in) from the front of the track roller frame casting and scribe a line parallel to the machine front casting face. This is to locate the front face of 6Y6834 Block.4. Make sure the mating surfaces of 8Y1388 Bracket Assembly and bolt hole areas are free of paint. Clean track roller frame area of paint and dirt in area to be welded. 5. Fasten blocks (2) and (3) to 8Y1388 Bracket Assembly using 7X0406 Bolts and 8T5361 Washers. Hand tighten the bolts. 6. Position a level vertically against the top of the hub bolt heads as shown, and record the reading.7. Align assembly from Step 5 onto track roller frame with front edge of front block on scribed line from Step 3. 8. Position a 133.35 mm (5.25 in) inch long bolt with nut between bracket and tractor frame to help steady the bracket as shown. Position nut at edge of bolt for adjustment purposes.9. Position a level on the inside bore of 8Y1388 Bracket Assembly as shown and verify that it matches the reading from Step 6. Fasten the track adjustment cover plate to the track roller frame, without the O-ring, before performing any welding to keep weld spatter from getting into the roller frame. 10. Tack weld block (3) to track roller frame as shown.11. Verify plate (1) will fit between blocks (2) and (3). If it does not, loosen 7X0406 Bolts until it does. Tighten bolts and tack block (2) to track roller frame.12. Weld blocks (2) and (3) to track roller frame with a 10 mm (0.39 in) fillet (two passes). Alternate the weld location to reduce heat build-up. Weld blocks on three sides (exclude lower back).13. Position plate (1) between blocks (2) and (3) so chamfers are on the track roller frame side. The plate should be positioned 8 mm (0.31 in) from the slope edge of blocks (2) and (3), parallel to slope, and resting on the track roller frame. 14. Tack, then weld plate (1) to blocks (2) and