I started taking apart the rear end to change all the rusty bolts, replace the bearings, and grease everything up. First think I noticed was all the nuts and bolts are NOT metric. I also noticed the rear diff is just a standard 3/4″ go kart diff. I am thinking about using a 3/4″ live axle and adding a disc brake where the pedal sprocket is. 

Last night i took it completely apart and cleaned out the original grease and put in fresh grease.