Thank you everybody for your suggestions.
Bearings are new. Steering head was tighten. Alignment of the tub wheel was checked when I installed a new tire.
There is no brake on the side car. The bike has front double disks and rear single disk. I'd like to see a picture of your wheel Jay if you can send me one.
I was seriously considering a subframe for the reasons mentioned here. I started to look around for options.
I will experiment more and see if I can eliminate the wobble.