Thanks again guys - OK with all your help I decided to remove the rear brake mechanism ( this was a pretty bold move for me). In the process of removing the rear brake, I became more and more puzzled trying to understand why the disc was jammed. I soon realized that there was no way that the disc could spin between the two pads even if the pistons/pads were open. Bottom line was the whole breaking mechanism was not sitting in the correct place and that the disc was tilted. After many minutes of trying to figure out how the part of the frame where the brake is attached could be bent - I realized that the frame on the opposite side was bent. This is causing the axle to be a little lower on the left than the right. This slight difference is messing-up the alignment of the disc with the brake mechanism. I continued taking of the brake, which I gently had to tap out with a hammer. Once it was off the wheels where able to spin. Infact, I was able to drive the Kart, to confirm that everything worked - and it did. Problem now is there is a very loud squeeking noise when the kart is moving. It sounds like it might be bearings or something scraping because of the axle being un even,
So now the question is - is there a way to get the frame-swingarm straigtened. It is buckled, directly above where the axle connects to the lower swingarm.
Thanks again - I am so thankful for all your help