Hi, we are about to return to caravanning. We have a Kodiaq with an electric retractable towbar which was greased for our trailer tent but since not being used has rusted with water collecting in its cover. I know it needs to be squeaky clean for an alko stabiliser, any advice on how to achieve that? How to maintain that?
Thanks
Absolutely true, it does need to be 'squeaky' clean for the damped Alko coupling, otherwise you risk it 'groaning' LOUDLY in protest, and it really is quite disconcerting how loud and intrusive into the very body of the car it can be! On the other hand, if ball still greased then coupling wont damp at all, and the damper pads will need replacing before it can be made to work properly again!
Hoping that your corrosion on the ball is not really anything much worse than surface discolouration, not actually deep pitting which may cause excessive wear on the damper pads in the coupling (they are like brake pads).
Firstly degrease the ball with Brake Cleaner (available as an aerosol from car parts retailers, Screwfix, Toolstation and the like) and paper towel or a rag. Examine the ball, checking both for rust AND paint (ball has to totally free of paint as well!). If only light rust/minimal paint, then a sanding pad (like an oversize pan scourer) does a pretty good job as you can cup your hand around the ball with it and easily reach all of the surface. If heavier corrosion/thicker paint, then strips of emery cloth (around 120 grit) pulled back and forth over the ball usually does the trick. Finish off with the sanding pad to give a smoother finish. Degrease again to get all the dust off.
Avoid using power tool sanders, some risk of taking too much metal off and reducing the ball dimensions more than is desirable, and/or flat spotting it. A wire brush would be OK, may even be necessary if deep pitting.
As to keeping the ball rust free between uses, I use a tennis ball as a ball cover, it really doesn't seem to acquire anything more than the lightest hint of rust over the winter months when unused. I keep a sanding pad in the car, and give the ball a 'polish' before every use.
Unfortunately putting anything like WD40 or silicone on the bare steel ball to protect it from rust is detrimental to the coupling damping pads, so you'd have to be very vigilant and remember without fail to degrease thoroughly before use!
Worth giving the pads inside the coupling a spray with Brake Cleaner and a wipe over from time to time, they get a build up of dust and can contribute to the 'groaning'.
If a s/h caravan, use the damper pad wear indicators on the coupling to ensure that there is still life in the pads and they are performing their function. Quite easy DIY job to replace if necessary.
Use the sponge sanding blocks. Home Bargains have them or B&Q. They wrap around ball as you go. Keep some with you & give it a quick sand & wipe with clean cloth before you hitch up.
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