I thought I would post these pictures for those who have not opened one up.
I pulled my Shimano Pedals, 520's I think, and was going to transfer them to my new bike. One of the pedals would not spin freely so I figured I had nothing to lose by taking it apart to see if I could figure out what was wrong or maybe fix it. I was very suprised to find a large part of the pedal to be a plastic/rubber shell. The problem turned out to be that the top two nuts had tightened somehow and were putting too much pressure on the bearings. I regreased the whole thing and used some blue locktight on both bolts hopefully to keep them in place. Right now it spins free and has no free play.
Weird thing is, I never noticed anything when they were on my other bike.
Someone tell me what I missed if you would. I have never opened one of these up before.