Robert included the following instructions:

The upper brackets have two # 43 drill holes  which can be used as drill guides for drilling the mounting holes in the top of the journal box.  The guard should be on the bracket when using it as a drill guide. The bracket should fit on the 1/4 inch shelf with the holes lined up with the two vertical ribs on the journal box.  After the holes in the journal box have been drilled and tapped 4-40, the brackets should be re-drilled #33.

The lower bracket is mounted on the cover with 4-40 screws, making sure the screws do not  put pressure on the bearing. The lower bracket is secured to the guard with soft solder. The assembly is then removed from the journal box and drilled through the bracket from the back and the bracket tapped for a 4-40 screw.

I followed Robert's instructions except for soft soldering the bracket to the guard.  After mounting the bracket and the guard I drilled through the guard into the bracket with a #43 drill.  I tapped the hole in the bracket 4-40 and enlarged the hole in the guard with a #33 drill.  I used button head cap screws through the guard into the brackets.   The brackets were attached to the truck with hex head screws.

 

This shows the guard with brackets attached after I powder coated the assembly.
This shows  the guard attached to a truck.  The upper bracket has two screws into the top of the journal box.  The lower bracket has two screws into the cover plate.

 

The photo above shows the gear guards on Cass 5. The guards are probably not original. Robert's design follows the the gear guards shown on the right.

 

The drawing above shows the three pieces of Robert's gear guard design.   I measured the dimensions from the pieces and they might be off slightly.  The hole for the screw through the guard into the lower bracket is not show.   This hole will be drilled after the brackets and guard have been attached to the truck.

 

Robert was kind enough to pass on the above photo of the die he used to form the guard.  His described the process as follows: The guards are made of 1/16" X 1" brass which is available at our local Ace Hardware store.  The brass is heated until it glows and then quenched in water.  A 5" piece is then partially bent and placed in the forming fixture and forced closed in an arbor press. The fixture and brass are then placed in a vise and the mounting tab bent about 45 degrees with a hammer.   The brass is then re-heated, quenched, and pressed again   The tab is then finished by bending it to 90 degrees.