Kid Coaster Brake Fix

This doesn't even show how bad the coaster brake was malfunctioning. I could almost get a full pedal rotation at times before/after brake engagement.

Step #1: Remove wheel from bike. 

Begin disassembly of hub. I prefer to leave the cog side together (it has a cone setup) and disassemble from the non-drive side. I use the coaster lever as leverage to loosen the nut. 

Lay out each part in the order of disassembly. Seems obvious, but reassembly is much easier this way.

After cleaning everything, reapply lube to bearings and contact surfaces. I prefer to use Park Tool Polylube for hubs such as this. Begin reassembly process. 

This is the driver for the coaster brake process with the coarse thread. 

Apply lube to bearing here. 

Reinsert axle and coaster driver assembly. Be sure to do this from the correct side, as each side of the hub has a different diameter. This should be the smaller of the two since the other side needs to fit the expansion wedges. 

This spring-loaded piece threads over the coaster driver and applies pressure on the expansion wedges, activating the friction braking system. 

This is what they look like mated together. 

With the expansion wedges installed. This is the larger opening side of the hub. 

Lube and install this bearing.

Begin threading this cone/coaster placeholder. Don't thread on all the way. 

Insert this piece over the expansion activator piece, in between the expansion wedges and hold in place. You will thread the axle from the other side. 

Thread the axle in from this side. The nut and cone are locked together, so use a wrench on the nut if you have to.  The threads should be smooth at this point, however. 

With the axle completely threaded through. 

Install dust cover. 

Install coaster lever. This is effectively the cone wrench for preloading the bearings. Once the bearing play is removed, follow the next 2 steps. 

Install washer. 

Reinstall nut. As with most cone and bearing installations, a couple iterations are typically necessary to remove bearing play and have proper bearing preload. Once you have this step right, you're done. Reinstall the wheel. 

Much better braking and forward-pedaling reingagement. She's ready to keep on riding.