Putting the axel on top of the springs is a very crude way to do it. There is a lug that sits in a hole iirc and when the beam is on top it obviously doesnt locate, so you need to weld the clamps to the beam or it will slide from side to side when you go round corners! When i did my mk4 van 10 yrs ago i sent the leaf springs off to LEDA and they decambered them to whatever height i wanted. You also need to adjust the handbrake mechanism as it thinks the van is full of weight and keeps locking up the rear wheels.