ATC 200 rear axle

[mmwb]

I was pulling the bearings on my 82 atc 200 today. There is a sleeve that goes over the axle, between the wheel bearings (in the housing). It is a bit corroded. What is the purpose of this sleeve?

[Mobular]

To keep the center races apart while tightening the axle. Also without this collar, the bearings would collapse quickly due to the side loads placed on them during riding.