I have this older Dunlop bike trailer for my son, and the bearings for the wheels have gotten really loose. The wheels wobble quite significantly on the axles. I figured I'd take apart the axles to replace and tighten the bearings. However the bearings are unlike any wheel I've fixed before. There are no nuts on the axle, only a C-clip and some washers, and the bearings seem to be enclosed and attached to the wheel, I can't seem to get the darn things off! Even if I did, I don't know where I'd get replacement bearings or if that's even possible. Has anybody seen these types of bearings before and have any tips on how to service them? Thanks!