If you are paying for a caravan engineer to come out then he might as well do the whole job. Strip it down, clean up draw tube, ream bushes & replace damper. Dampers fail slowly, not all at once & if its banging then damper will be on the way out whatever you do with hitch. Once all that is done it will tow like brand new, you will be amazed at the difference.
UPDATE: The caravan engineer came round and said that due to the hitch having play in it this was definitely the issue. He greased it all and now there is no play and the hitch does not judder on the return. He checked everything else,all Ok,cleaned the pads with brake cleaner. I will have to hitch it up and check his prognosis.I must admit that the hitch does seem a lot more solid than it did.
------------- I have forgotten more than I now know
Quote: Originally posted by Bedlam on 24/5/2014
When the car is solo there is no knocking. Michell I will check the damper. I have noticed that the towbar is a very snug fit to the car. Even though it is all tight, could there be a slight deflection when the van is on the back?
I had this with mine. The back plate behind the towball was actually bent backwards by this time, as the tow hitch on the caravan was quite long at the front end. All I needed to do was have a spacer fitted twixt ball and housing. You can buy them from caravan accessory shops. But you do need to make sure you get the right width.