My sliding door is now squarely aligned.  My thanks to Jim Catterson for the
info.  The "U" hinge height is adjusted by the two bolts anchoring it to the
door.  I put a padded floor jack under the edge of the door, loosened the
bolts, raised the door with the jack & resecured.  After adjusting the striker
plate (pin) to match, everything works great.  It's nice to see straight lines
down the side of the van!

Thanks
Vernon