Hi Kieth, sorry to hear of your dilema.
Its no consolation but you are not alone,I have 3 customers who have had the same probs as you.
From what you say about your van listing leads me to believe that the rubber torsion arms have given up the ghost.The only remedy is to remove your vans axle and either repair or replace.
For example a 2nd hand axle for a 90Fleetwood cost me