Dex210 RR suspension mount help

[StuartH]

I cracked the plastic one on my dex210 at the weekend and ordered a brass replacement part. The brass part has a larger cup/ hole where the hinge pin goes into as opposed to the tight fit of the plastic version.

When I put it all together the whole rear suspension arm rocks side to side as there is nothing to clamp the pin in place. Is there something I'm missing or doing wrong here? Do I need to put something inside the cup to hold the hinge pin?

Sorry very confused?????