Rear shock-mount nut

I installed my Mega-Byte Jr's myself, but I replaced all the bolts that came with it. It was a used set, and the bolts were a little chewed up. So I can't tell you the size of the nut you have, sorry. To tighten that part up, I had to get a wrench on the nut then tighten it using the bolt head on the other side. There's no room to turn the nut on its own. You'll need to remove the lower shock bolt to get access to that bolt head. In case you haven't done your rear shocks before, be sure to put jackstands under the axle so it doesn't shift when you remove the lower shock bolt. Also make sure the bolt isn't bottoming out on the side of the Jr's bracket. If it is, you may have to grind down the bolt or buy a shorter one.

For anyone else who hasn't seen a set of Mega-Byte Jr's installed, the Jr's have a bracket that goes in between the axle and lower control arm. This changes the angle of the axle and helps reduce squat under acceleration. This bracket requires that you remove the bolt holding the lower shock mount on, and replace it with a longer bolt that goes through the shock mount and into the Jr's bracket.