Thanks guys for all the input. Pacerron, what is a back castor? I've never heard of one. Also I do not have height retaining chains on the front. I'll probably get a socket and spray the s### out of it and put some muscle into it to break them free. Then I will lather them with never-sieze.
The back caster assembly should standard with the BB60. The check chains are optional but great to use. You can control the front height and side to side level of the cutter with them while taking all the stress off your lower links. You can still use the lower links to raise the mower for transport or cutting in an area where you would dig in otherwise. Some folks constantly whine about their lower links drifting down. With the chains the front of the mower drops to the height you pick on the chains and stay there until you change it.
BB60 Single Spindle