Outboard Pinion Bearing

[8EL]

I purchased a Motive Power ring and pinion set, and note that the pinion outboard bearing journal does not have the same step relief machined as does the original. This has been noted by others as impeding the proper bearing preload setting on assembly.

The part I received had a journal diameter of 1.5765", the old part measured 1.573", as this part was received, it would have had to have been pressed on as can be readily realized by these dimensions.

To solve this problem I fashioned a mandrel to hold the pinion gear in the lathe from the end of the old drive shaft which is being replaced in this overhaul. This mandrel will be utilized also in the process I am working through to simplify differential setup. (At issue being the awkwardness of handling the full length drive shaft in the process, more on that on a later post.) The part was set up to a tolerance of .00025" total run out in the four jaw chuck. At 1.573" the Timken bearings being used are still a bit more than a slip fit. The final dimension that I turned this part too was 1.5725" and has the desired slip fit sought after.

This is a very important detail and should be maintained for proper preload set up. As others have noted it would indeed be very difficult if not impossible to have properly set the preload with this part as supplied.