Well, one of the trucks of my skate. During practice. I thought I was doomed to skate in rentals for the next couple weeks, but then Massacre happened to have an extra truck. Tossing it at me, he said, undo the bolt, take off the truck, and put the new one on the same way.
Check out this diagram of a skate that I found at quadskating.com. Lets just say that 24 hours ago, I did not know anything about parts 2 - 6. Not many numbers, but really - look at all those parts!
After removing the broken truck (simply taking a skate took to bolt #2) it was actually very easy to switch it out.
Why did my truck break? I suspect because it's been over two years since I got my skates, and apparently trucks matched for this plate are notorious for breaking. Anyway - no matter really...because I'm in the process of ordering new skates! But that's another blog for another day.
Lesson: don't fear your skates! Don't be afraid to take them apart if something is wrong. I even waited over a year before changing my wheels for the first time... sheesh! No worries. As Miranda Wrights says: Roller skates, the friends beneath your feet.