Usage:
776B Tractors;
777B, 785, 789 Trucks
This article supersedes the article with the same title on Page 1 of the March 4, 1991 issue of Service Magazine.
If the wheel bearing cone turns on the axle housing, it can result in wear on the housing. Use this procedure to prevent the rear wheel bearing cones from rotating on the axle housing.
This procedure is applicable to all of the above tractors and trucks since first production. It involves slotting the bearing cone so that it will fit over a ball which is installed in a hole that is drilled in the axle housing. The ball will prevent the bearing cone from rotating on the axle housing.
Disassemble the rear wheel group, and remove the wheel bearing cones. Chart A indicates which wheel bearing cones are used in the rear wheel group on each machine.
Machine a 9.5 mm (.37 in) radius groove, 3.0 mm (.12 in) deep into the inside diameter of the bearing cone. See Illustration 1. Keep the bearing as cool as possible during the machining operation.
Illustration 1. Location and dimensions for groove in bearing cone.
Drill and ream two holes in the axle housing as shown in Illustration 2. Chart B provides dimensions (A) and (B) for each machine. The two new holes must be in line with the Automatic Electronic Traction Aid (AETA) sensor hole in the axle housing.
Illustration 2. Location and dimensions for new holes in the axle housing.
Install a new 4B9784 Ball (.5 in) in each of the new holes in the axle housing.
Assemble the rear wheel group. When installing the modified bearing cones, the new groove on the inside of the bearing slides over the new ball in the hole in the axle housing.