Rigging a Front End Loader for Animation

Hi y’all. Been doing some more work on my front end loader:

(Almost) fully rigged articulated front end loader

I’ve run into a small problem ( and just realised W.I.P. wasn’t a support forum :o ).
I’ve managed to get a wheel rotating, using a python expression and an Empty, but whenever I try to parent the empty, or constrain it, the rotation doesn’t happen. I have the whole thing following a curve, so I f I hit play, the wheel will move, but not rotate. If I select the empty (wheelSpFL) and move it, the wheel moves and rotates.

I’ve uploaded a.blend file, it has a child of constraint on the empty. Any ideas people?

Solved that problem. It was painfully simple. Carry on.