Converting an M01 motor from LH face plate to RH face plate position for the gear box
(courtesy of Steve Tyng, editted by Joe Sommer)

You must remove the screws on the motor face plate to rotate the gearbox to the 
RH position.  The front of the gearbox needs to come off to remove the fourth screw.
Do this in a clean environment to prevent anything from getting into the gearbox when 
it is open.

Before you begin the first thing you need to do is tape the back cover in place 
so it will not pop off when you remove the four screws.  If the back plate does 
come off it will be very difficult to get it back on because you will have to 
depress all four brushes at the same time to do it. 
 
Opening the gearbox is relatively simple.  Before removing the gearbox cover mark 
its position so you can put it back together the same way.  Use a screw driver that 
fits well because the screws are made of a soft metal and they are easy to strip out.
Remove the four screws.  The cover may have to be pried off.  An old chisel works well. 

Pull the gear box cover straight out and the shaft with the gear should come out with 
it.  The bearing that holds the back side of the gear in place may or may not come out 
with this assembly.  If it does watch for any shims and spring spacers that will be 
behind the bearing.

You can now access the fourth screw for the face plate.  Remove the four casing screws 
and rotate the front cover in place 90 degrees and reassemble.  Do not be tempted to 
pull the front cover off because the armature will come out with it and you will have 
the problem of refitting it to the brushes on the back cover.