Washers/shims in Bully 2 axles
 

Got another question for those with more knowledge/experience than I with the Bully 2 axles.

I've started tearing down these axles to replace the stock bearings with a set of Fast Eddy bearings. Did the front, noticed nothing out of the ordinary and they went back together fine. As I start the rear axle, I notice a brass shim (8mm OD, 5mm ID, .25mm thick) on the outside of of the outer most bearing, right behind the pin for the wheel hex. The front had no such shims so that's why I took notice. When I start the other side of the rear, I notice the same shim on the inside of the outer most bearing.

So my questions are...

1. What side of the outer bearing does this shim belong? I assumed it would be on the outside to protect the bearing from debris but I figured I'd ask.

2. Should the front axles have any shims around the outer most bearing? As I said my front axles had no shims at all.