I'd repair it by pinning it and then using a 2-part epoxy to glue it.
By pinning it, I mean that I would cut a little groove into the piece, across the crack, and insert a piece of wire, such as a piece cut from a paper clip or a brass rod (available at hobby shops, model railroad shops, or online), and then secure that with a 2-part epoxy glue. When it sets up, it'll be a strong join that will resist further cracking.
A more radical version of pinning it would consist of cutting the piece completely through at the point of the crack, and drilling holes in each side to accept the pin. That would mean bending the shaft until you could have enough room to drill the holes and insert the pin. But that would be even stronger.
When I say "drill", I mean using a fine drill bit chucked into a pin vise, and drilling it by hand.
The trickiest fix would be soldering. That would leave you with a homogeneous piece in the end, but the risk is melting the piece. I wouldn't do that, myself.
I'd probably strip the piece first, too, just to be able to end up with a consistent color, instead of trying to match the paint for the repaired area to the rest of the cart.
Hope that helps!
Prost!
Brad
