I've missed your inspiration Wayne. When you are setting it up, make sure you put some scales on the towball and ensure the towball weight doesn't change too much. It shouldn't cos your using the original wheel well most probably, but there were vans that had rubber suspensions etc that had certain configurations for a reason. But here's a thread and forum that may be of interest.
http://caravanersforum.com/viewtopic.php?f=2&t=7558&start=40I think some things that ppl do or don't do.
-don't choose an over rated spring on an old light caravan.
-choose a controller with manual over ride slider so that you can control a sway, especially on an old car. So if you got a sway up down hill, rather that gently applying brakes, u can slowly brake the caravan only, to get rid of dangerous sway. Normally more common on light combinations.
-always consider how you can accommodate the original lowest ride height first like the others said by changing the hitch or the ball/towbar mount.
-simulate the loaded weight of both vehicles at trial fit.
-I would use a square axle over round.
-older cars tend to have low tow balls.
Also make sure you always use bars. It doesn't matter if you have a level tow vehicle (four wheel drive ppl don't get this a lot of the time), so regardless how level it looks, it's the ball weight that pushes down that still take more weight off front wheels. So bars are for brake balance not only levelling. Brakes on car lock up with less weight on front wheels.
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