Due to the 2-piece U/C arrangement, when this plane lands the forces through the main gear ar effectively trying to "pry apart" the centre join.

Do what several of us have - make a metal plate about 50mm square (sorry, I'm at work, easy to figure out with the plane handy!) and drill a hole near each corner to match the inner 2 bolts of each main gear mount. Re-mount the main gear with this plate inserted over the top, and you have your 1-peice gear, no longer levering the wing join apart.

I got some matching Humbrol blue paint, and you'd never even notice it. Won't solve all the issues, but solves this one.

Cam