The lower spring mount on the rear control arm of a Vanagon is becoming a part that is rusting out more and more. You can replace your entire control arm, but if the lower perch is the only thing that has gone bad, why not just replace that. I would clean up the control arm, paint it with rust inhibitor paint, then weld one of these on. Then you want to paint this part, and install a new lower plastic bushing before reinstalling the rear spring. You should be good to go for many years to come.