New towball - to sand or not to sand

Whether to remove the paint or not has nothing to do with the make of car or that of the caravan. It all depends on whether the hitch has an integrated frictional damper such as the AlKo AKS3004 or Winterhoff WS3000. Such hitches rely on a completely clean towball, free from paint or other contaminant, to work properly.

It is on a modern Alko chassis I think and so remove paint from the ball

The black paint will be rubbed off by the friction pads of the hitch, the paint fragments will then become embedded in said pads, causing noise and increased wear.

 So as said for us caravanners we must remove the paint.

I wouldn't sand it down, bit harsh and the paint is very stubborn.

If your dealer wont do it before fitting, I used with great success a hand held angle grinder with a wire brush twisted cup attached, very easy, thorough and relatively quick with no damage to the metal ball I could see.

all ways been told to remove the paint and sand down till it clean and smooth

Soul destroying job. I used to soak the paint off with solvent and finish with wire wool but last one even resisted solvent! Used a 3m paint stripping wheel which takes off the paint/plastic coating and polishes the ball same as this one 

https://www.screwfix.com/p/surface-preparation-wheel-with-arbor-100mm/31074?

Emery paper does the trick no problem at all