SEAL 8G0578 - Caterpillar

New pin assembly in power angling C-frame group. A 9W9480 Pin Assembly was then used. Even with a welded-on retainer and a spacer, the single bolt continued to loosen and/or break. Distortion of the retainer plate was also evident indicating that a high rotational force was being generated by the pin.
A 6Y2915 Pin Assembly (two-bolt) was then used to provide additional retention force, but bolt loosening and breakage continued.
A new 6Y4025 Pin Assembly is now used which has a thicker retainer plate welded to the pin. The retainer plate also has two bolt holes to hold the pin in position. The new pin also has a lubrication fitting which will lower rotational friction and eliminate pin noise.
The new 6Y4025 Pin Assembly is effective with 9DB1323, 8PB2879, 2AC574, 3AC626 can be adapted to all earlier D4H Tractors equipped with power angling tilt dozers.
Procedure to install new pin assembly on earlier tractors
1. Drill and tap the existing retainer bolt hole (5/8"-11 thd.) to accept a 1A0458 Bolt (3/4"-10 by 1.75").2. Install a new 6Y4025 Pin Assembly in the C-frame.3. Align one of the holes in the retainer plate with the newly tapped hole in the C-frame.
Location of tapped holes in C-frame bracket.4. Install one 1A0458 Bolt and 7P6820 Spacer through the retainer plate.5. Mark the location for the second hole to be drilled and tapped in the C-frame. Care must be taken to make sure the two holes are correctly located (spaced) so the pin loads are shared equally.6. Remove the bolt, spacer and pin assembly.7. Drill and tap a new retainer bolt hole to accept a 1A0458 Bolt (3/4"-10 by 1.75").8. Install the new pin assembly using two 1A0458 Bolts and 7P6820 Spacers.