Removal of Chipper/Shredder Wheel

I have an MTD Yard Machines Chipper Shredder Model 24A-462G352 but am sure that my problem relates to other Chipper Shredder models and brands. My Chipper Shredder has a flat tire. Some engineering genius had the Chipper Shredders manufactured with the tire valve stems of their "wheel assemblies" facing the "frames" instead of facing out - where a jump starter powered tire inflater could be attached.
This engineering genius had "push caps" placed over the ends of the "axle assemblies".

Having been unable to get the valve of the tire inflater to properly attach to the valve stem of the "wheel assembly", I sought to remove the "wheel assembly" from the "axle assembly". To do this, I have to first remove a "push cap".

The parts diagram in my "Operator's Manual"'s "Chipper Shredder Model Series 462 thru 465 "parts diagram" does not show what might be hidden beneath the "push caps" or otherwise securing the "wheel assemblies" to the "axle assemblies".

The "push caps" are secured to the "wheel assemblies" and/or "axle assemblies" in a manner not shown in the "Operator's Manual"'s "Chipper Shredder Model Series 462 thru 465 "parts diagram".

It currently appears that I may have to break the "push cap" to discover how the "wheel assembly" is secured to the "axle assembly" because of the above ommissions.

 

Yes, those push caps are a pain. Under the plastic, decorative cap is a thin metal washer with tabs on the inside. When hammered onto the axle the tabs bend a bit and act like barbs on a fish hook to prevent the cap from coming back off. I usually pry them off and throw them away. Then I drill a hole in the end of the axle for a cotter pin.