Hi all, i have a swift challenger 2002. I want to seal everywhere on the outside. Do i really have to take all the rails off etc, or can i just apply sealer as it is. I have a few tubes of PU18. Many thanks!
Firstly, do you really need to reseal the caravan? Have you got a leak or are you thinking of doing it as a precaution? If you have a leak, are you sure that the seal on the rail is the source? Can you see where I am going with this? If there isn't a leak, it is sometimes better to leave well alone. However if you decide to replace the seals, be aware that it is a messy, time consuming job.
The first job is to remove the plastic strip which covers the rail mounting screws then remove the screws. On a 12 year old caravan, it is a penny to a pinch of snuff that they will be well rusted and the original hole in the caravan frame will be "nail sick". This is a situation where the holes left by the screws will have enlarged as a result of the screws rusting. In turn, this means that the rails will have to be re-drilled to one side of the original holes so that the new screws will be going into solid wood.
Having removed the screws, the next job is to get the rails off without bending or kinking them. The best tool to use is a 4" wide bolster chisel. This gives a nice wide base to use as a lever. If used very carefully, you can lever the rail free of the wall of the caravan without k.inking or bending and without damaging the wall. While it is pretty obvious, it may be worth marking which rail goes where with a pencil on the aluminium face.
The next job is to thoroughly clean all of the sealant off the wall and the rail so that you are down to the bare metal of the rail and down to the paint on the wall. Be aware that the paint on the wall of the caravan is printed on and is only microns thick. Do not be tempted to use a screwdriver or a chisel or similar tool. Inevitably, you will damage the surface of the metal. The best tool is a piece of wood about 1" or 2" wide by about 1/2" thick and about 6" long with one end tapered down to form a 1" or 2" wide "chisel". Use this to scrape the goo off, resharpening when necessary. Then do the same on the rails. When scraping, try to scrape towards the edge of the wall/roof corner to save spreading the goo over the wall. Once the goo is off, clean off any remaining sealant with lots and lots of kitchen roll or rags and white spirit until it is all gone and the paint and the rail are scrupulously clean. It is best to wear an overall or old clothes which can be discarded after the job is done. Don't go and sit down in the lounge for a break or sit on the caravan upholstery as it is highly likely the your sit-upon will have bits of goo on it.
Once it is all cleaned up, have a look at the screw holes in the frame of the caravan. You may get away with putting the new screws back in the old holes but it is going to be 50/50. If not, re-drill the holes in the rails using a suitably sized drill, slightly to one side of the old hole on the centreline of the rail. There is usually a shallow groove in the recess where the screws go which will give you a bit of a guide. If you use one of the good screws which you have removed as a guide as to diameter and length, get some new screws. The best and cheapest place for screws is Toolstation or Screwfix where a box of 200 screws of the size you will need will cost you about £2.00. Countersunk scr ews are perfectly adequate.
Now we come to the replacing of the rails. You must use a non-setting sealant. This allows the bodywork of the caravan to expand and contract without breaking the seal. Using a sealant gun, apply a continuous bead of sealant above and below the screw holes. The bead must be continuous or the seal will leak. Having selected which rail to start with, offer it up to the caravan and realign it using the old screw holes as a guide. Once you are satisfied that the rail is in the correct position, put a screw or two in the old holes to hold it while you put a pilot holes in the caravan frame through the new screw holes in the rail. Insert and tighten the new screws, remove the temporary screws and replace with new screws. Offer up the next section of rail making sure that the ends of the two rails are properly aligned where they meet otherwise you will have problems getting the awning to run through. Make sure that there is a gob of sealant on the caravan wall so that the adjoining rail ends are bridged. Clean any stray sealant out of the awning groove. Repeat the process as before. As each section is attached, wipe off any excess sealant with kitchen roll or similar.
When all the rails are back on and you are satisfied that there are no breaks in the seals, step back and admire.
The above guide to doing the job is given in good faith. It is up to you to take care and make sure that there are no breaks in the seals. If there are, start all over again.
Again, are there any leaks or is this a precautionary exercise?
Thankyou Dickers for the explanation on how to do it. Quite a big job! We haven't got any leaks, just was being cautious. Trying to make sure the van is sealed so she will last us for a good few years!