Here's the straight poop from Whizzer. The new rear disc brake assembly with freewheel sprocket won't fit unless extensive frame cutting and welding are done to accommodate the wider assembly. The rear drum brake assembly (wheel and all) will fit into the older model frames.
Coaster brakes can be overheated by the slight unconscious pressure of resting one's feet with slight backward pressure on the pedals. The friction caused heat will melt the grease from the bearings and allow it to flow into the hub area where the "shoes" make contact.
My Whizzer's rear bearings were sprayed with WD-40 by the previous owner. I cleaned out the hub, but there was a slight film still on the inner surfaces. I must clean out the inner part of the hub, again, this time with a solvent to ensure the contact area is absolutely dry.
As it is right now, the coaster brake is either nothing, or fully locked up when I apply it.
This time I'll do it right.
