Usage:
Introduction
A new improved pivot shaft enclosure tube, plus extra parts, is now available from the Parts Department for replacement of the existing enclosure tube. Installation of the new tube will improve the service life of the machine.
Reference: Service Manual, Parts Book, Operation and Maintenance Guide
Necessary Parts
Modification Procedure
| NOTICE |
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All welding must be done with E7018 welding rods, 3 mm (.125") in diameter at 120 Amp.,and DC reverse polarity. Do not allow the pivot shaft bearing bores to be heated above 94° C (200° F), or distortion of the bores may occur |
1. Remove the bulldozer, tracks, track roller frames, bottom guards (two rear), and power train oil tank. See the Service Manual for the correct procedure.
2. Using a dial indicator as shown, check the vertical clearance between the pivot shaft and the bearings in the mainframe. Replace the bearings if clearance is more than 1.5 mm (0.060").
3. Disconnect the pivot shaft oil fill hose from the pivot shaft enclosure tube.
4. Remove the pivot shaft from the machine.
5. Remove the bolts that hold hydraulic manifold assembly (1) to bracket (2) [located on the right side of the pivot shaft enclosure tube].
6. Clean the oil from the inside of the pivot shaft enclosure tube.
7. Weld two 37 × 50 mm (1.5" × 2.0") or larger crossbraces (3) across the bottom of the mainframe as shown. Use 8 mm (.31") fillet welds 75 mm (3.0") in length.
These crossbraces will help keep the mainframe sides plates from moving due to heat distortion during cutting and welding.
8. With an air carbon arc torch or similar tool, remove welds (A) and remove existing tube assembly (4).
NOTE: Be careful not to cut into the mainframe.
9. Grind the area smooth.
NOTE: The old tubes (end) fit into a counter bore in the mainframe side plates. The new tubes (end) have a larger outside diameter and fit flush against the side of the mainframe side plates.
10. Mark the mainframe side plates at the dimension shown at four locations [measuring from the inside diameter of the bearing not shown in the illustrations above] so that the flared ends of the tube assembly can be centered relative to the pivot shaft bearings in the mainframe.
NOTE: These marks must be accurate to ensure adequate clearance between the pivot shaft and tube assembly.
11. Measure distance (B) between the frame side plates as shown. Compare this dimension with the length of the 6Y3028 Tube Assembly.
12. If the tube assembly is longer, grind off the necessary amount of material from each end of the tube assembly.
13. If the tube assembly is shorter by 4 mm (.16") or less, the tube assembly should be installed so that the space is equal on both ends.
14. If the tube assembly is shorter by more than 4 mm (.16"):
- * Make two sheet metal rings (5) to provide backup for the weld on each end, or;* lay a bead of weld at the same circumference as the tube assembly end and grind the weld bead down to the proper height to provide weld backup.
15. Carefully and accurately position the tube assembly between the side plates and align with the marks made earlier on the side plates in step 10.
16. Fitting (6) on the tube assembly must be on the left side of the machine and positioned 10° forward from vertical as shown.
NOTE: The correct angle will result if the bottom corner of curved plate (7) is 28.5 mm (1.12") above the bottom surface of the center portion of the tube assembly.
NOTE: This dimension can be checked using a carpenters level as shown.
To make this check, put the level parallel with the chassis. Then put the level in the same position on the tube assembly and check the dimension [(28.5 mm (1.12")].
17. Fabricate four steel blocks (8). The blocks should be at least 37 mm (1.5") in length × 25 mm (1.0") in diameter or 25 mm (1.0") square.
18. Weld the four locating blocks (8) to the left hand mainframe side plate as shown. Locate the blocks so that the tube assembly can move from side-to-side but not move up-and-down or fore-and-aft.
19. Tack weld the right end of the tube assembly to the right mainframe side plate.
| NOTICE |
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Do not tack weld the left end of the tube assembly to the mainframe side plate or to the four locating blocks at this time. The tube assembly must remain free to slide in the four locating blocks after welding on the right side is completed and allowed to cool to minimize distortion to the frame and bores. |
20. Weld the right end of the tube assembly to the mainframe side plate at location (C) as shown. Use a 20 mm (0.8") fillet weld with a 2.5 mm (.10") penetration.
21. After the weld on the right side has cooled, weld the four locating blocks to the outer edge of the tube assembly at location (D). Use a 6 mm (.25") fillet weld as shown.
22. Make the first weld pass between the four locating blocks at location (E).
23. Cut the four locating blocks off and complete the first weld pass. Make the remaining weld passes needed to achieve the 20 mm (0.8") fillet weld around the tube assembly.
24. After the weld has cooled, install the pivot shaft.
25. Remove the crossbraces that were installed in step 7 and grind the area smooth.
Installation of Bottom Guard and Hydraulic Manifold Mounting Bracket
1. Put new 6Y1304 Bottom Guard rear (1) in position on the machine and install the existing mounting hardware in the two rear holes at location (A).
2. Make sure the front of 6Y1304 Bottom Guard (1) aligns with the rear of existing guard (2) at location (B), which was removed earlier.
3. Using the bottom guard front mounting holes as a locating guide, tack weld two 7T8968 Plates (4) and one plate (3) on curved plate (5) [both sides].
Position plates (4) 10 mm (0.4") from the edge as shown.
4. Complete the weld around plates (3) and (4) with the following weld specifications.
- * Location (A) - 8 mm (0.3") fillet weld with 2.5 mm (.10") penetration (both sides - four plates).* Location (B) - 8 mm (0.3") fillet weld with 2.5 mm (.10") penetration (four plates).* Location (C) - 12 mm (0.5") bevel groove weld (two places).* Location (D) - 12 mm (0.5") bevel groove weld (two places).
5. Weld 6T9389 Plate (6) in position on the bottom guard mounting bracket at the dimension shown (right side).
6. Weld 7J7778 lug (7) to the inboard side of the left frame rail at the dimension shown.
7. Position the pivot oil fill hose as shown and install the 8T7529 Clip (8) with a 0S1621 Bolt and a 5P8245 Washer.
NOTE: May be necessary to use a 8D9947 Clip in place of the 8T7529 Clip.
8. Reassemble the machine. See the Service Manual for the correct procedure.
9. Fill the pivot shaft oil compartment and the power train oil tank. See the Operation and Maintenance Guide.