It shouldn't be the imperial ball as I only had the tow bar installed just recently as the Pajero didn't have one when I brought it, some interresting reading on this subject here
http://caravanersforum.com/viewtopic.php?f=2&t=33011
That make for some good reading
@axl
Maybe your right it's the bolt on the hitch that is not the right shape to match the tow ball. I would assume that it's been over tighten or damage in some other way and now it does not line up with the tow ball.
If it was me I would purchase a new hitch bolt and a new tow ball and see how is goes from there.
Quote of another forum >>>
This how I have adjusted the coupling ball adjusting bolt.
Both tow vehicle and trailer must be on level concrete with brakes not applied to trailer. Fit safety chain between vehicles.
With tow ball fitted to towbar tongue.
Lubricate tow ball with oil of choice.
Fit trailer coupling to tow ball.
Use large screwdriver to prevent adjusting bolt turning.
Undo lock nut on the coupling with a ring spanner, several turns.
Use large screwdriver to turn adjusting bolt clockwise until the adjusting bolt touches the tow ball.
Test to see if the coupling can be removed from the ball.
If the coupling can not be removed from the ball, turn adjusting bolt anticlockwise, using the large screwdriver, until the coupling can be removed from the tow ball.
Fine tune the adjusting bolt setting by turning it clockwise then anticlockwise one sixteenth of a turn, each trial, until the coupling can be placed on and removed from the tow ball without binding.
Note direction of slot on the top of the adjusting bolt.
Tighten lock nut on adjusting bolt using ring spanner, using screwdriver to ensure the adjusting bolt does not turn from chosen setting.
The adjusting bolt does not play any part in securing the ball in the coupling. It only serves to minimise the internal gap and reduce coupling noise. There is no problem in slackening it off a bit so that the coupling goes on and off easily - your van ain't gonna fall off! There are a number of couplings available with no adjusting bolt at all.
With a WDH fitted, you will have a much higher down force on the coupling in any case, which will eliminate any excess movement and rattling.
If you have a problem disconnecting your van, simply slacken the bolt off until it works more easily, it's not that crucial.
, when I towed the van home it jumped/lifted up on the tow ball a couple of times, should I be concerned about this? The van was sitting a little hi at the front but I had 30psi in the airbags and the van was empty. Once I load a bit of gear in the front boot and I drop the pressure down a touch it should sit nice and level and I plan on using a hitch lock (as I do with my boat for trailer security) when towing so there is no way it can jump completely off the ball.
