[T-Man]

It starts with rust. The best way is to remove the wheels and wire brush them out.

But the tabs breaks at the orange arrows. It's not the end of the truck. Just fix it. First you set the axle back in and use super glue on the joint.

This hold everthing so you can support the back with two part epoxy.

It holds but may not be as strong as the original joint but it works for now.
I may tag it with some red paint to identify it as a repaired truck.

 

[Big Ed]

How about a wire wheel on a dremel tool?

Just leave it all together so you don't have to repair it.

 

[T-Man]

Up until now I have never broken one. I like to remove them if they are really bad. I always use the dremel Ed, I just didn't get specific. Now, I know to be careful and they are repairable if you have the pieces. I have three newer hoppers and only one broke.

 

[T-Man]

Plastic sometimes break. So I reinforce the knuckle to prevent it.