jak Posted September 30, 2015 Share Posted September 30, 2015 Just back from a 5 week trip to France during which the Dethleffs Heki 3 skylight developed a significant leak that I temporarily overcame with a wrap of plastic tape along the external roof/skylight joint and parking the van so it was sloping forward. Suspect the problem is along the leading edge where a shallow pool of water tends to be created behind the cab/body joint. The van is 7 years old and this problem has not occured in my 5 years of ownership but on investigating the problem after my return I found there is evidence that the previous owner may have experienced a similar problem. Unfortunately he or the dealer seem to have made a botch of re-seating the external frame - some of the fixing brackets are skewed on their seatings and additional screws have been used to connnect the internal and external frame. I have made a cursory inspection from within the van and there is no evidence of any damage to the outer frame, screen, hinge fixings,etc. I do however recall snagging the roof on a small overhanging branch earlier in the summer whilst parking up and wonder if this could have disturbed the seating without damaging the actual frame. Otherwise I suppose it could just be a time related sealant failure possibly hastened by high temperatures generated under the French summer sun. I have attempted to tighten the outer bracket screws in the hope that the pressure may reseat the frame but access is severely limited with the outer frame in place. On our return to the UK I had intended to remove the Heki and reseat it. However I have hit a problem, in that the Dethleff has a wooden frame around the skylight that includes a series of downlights and the frame prohibits the removal of the Heki's internal frame. I can see no obvious means of removing the wooden decor frame and would appreciate advice from anyone who may have successfully tackled this task. I have inspected the external interface of the skylight and roof and was somewhat suprised to find there doesn't appear to be any sealant along the external joint face. In fact the lower lip of the Heki frame seems to be approximately 1.5mm above the roof deck and the void extends approximately 5mm below the lower lip. I had presumed that when seating the Heki external frame on the roof the sealant would have filled this void but I am unsure of the precise detail and from some of the related info it would appear there may be a rubber seal/gasket between lower frame and van roof which may prevent/impede sealant movement in this direction. Currently other than allowing a dealer to undertake the work my options for affecting a repair to the skylight appear to be limited to attempting to caulk the outer void with a suitable sealant. I have a modicum of experience with sealants in an industrial background and appreciate this would theoretically be a difficult task given the need to clean the joint faces and introduce a non setting sealant into such a small void and achieve an effective and durable seal. However, ever the optimist, I wonder if anyone has successfully accomplished such a task and if so can they advise on the materials used. I am particularly wary of how one can effect such a seal under the hinge brackets where access appears to be very limited. Link to comment Share on other sites More sharing options...
flicka Posted September 30, 2015 Share Posted September 30, 2015 Hi Jak I have no experience of refitting a rooflight, but the schematics on this site may help. http://www.leisureshopdirect.com/caravan-spares#hashJumptohereSchematics If the roof light shown is not the one you have you can select correct one on the right side of the page. As you summised it is important to clean off any old sealant before resealing. Silkafix is generally recommended by many forum users. A search of the forum should give which No. is required, but it is stocked by many caravan dealers. Just check it is of a recent batch date. Link to comment Share on other sites More sharing options...
Billggski Posted October 1, 2015 Share Posted October 1, 2015 I have a 2009 Dethleffs, and recently replaced the rubber seal around the Heki 3 rooflight, but that was a simple job. Yours appears to been have caused by the previous owner, and then yourself(?) catching it an overhanging branch. So easy to do. The diagram above may help with the Heki itself, but getting at it is the problem. The Dethleffs owners club are very helpful, if very difficult to contact, and are having a get together at the NEC show next week on the Dethleffs stand. That may be a possibility. Try Facebook, dethleffs-owners club, I think. I would use a flexible mastic rather than Sikaflex, which is great, but sets to a permanent, if slightly rubbery, seal. Link to comment Share on other sites More sharing options...
ken the kontiki Posted October 1, 2015 Share Posted October 1, 2015 We're in a similar position to Jak with an 8 year old Heki 3 dripping over the rear bed. For the moment, we've run a bead of non-setting mastic around the outside until such a time I can remove the external hatch frame. One thing I have gleaned is not to use Sikaflex 512 caravan as, although it's a flexible adhesive/sealant, it will stick the frame to the roof. Not ideal if you ever want to remove the hatch again at any time. Also found that the flange part of the screws used on the mounting blocks were not even in contact with the blocks themselves. I can only surmise that over time the original mastic has become hard and brittle and given up. If I stand on the roof next to the hatch, the roof flexys by 2-3mm and opens up a gap between the hatch and roof. Tightening the screws slightly has at least stopped this. As it hasn't rained since I sealed the hatch and therefore no pooling of rainwater on the roof, I can't say how effective our temporary repair will be. Suffice to say that at some stage the hatch will have to come out to do a proper job. Link to comment Share on other sites More sharing options...
jak Posted October 1, 2015 Author Share Posted October 1, 2015 Thanks guys: Flicka, I have looked at the LiesureDirect site and in particular these plans which are quite helpful and just about all that is available from what I can see. Billggski - I had considered trying the Owners Club which in some respects shows how desperate I am getting as I find them elusive to say the least. It seems an odd way for Dethleff to communicate with their UK client base and I have seen it go thru what I believe are one or two transformations over the years and it still seems to be something of a hotch potch. Given that the average punter in this 'club' has invested over £50K to be a member one would expect something somewhat more impressive - it reminds me of those old corner shops with the bell on the front door that you had to keep opening and closing innumerable times before the old codger popped his head through the curtain from the adjacent sitting room. Ken I agree that a non setting mastic is ideal and would be reluctant to use Sikaflex in this location given that it will ultimately need to be replaced. Can you recall what you used? Link to comment Share on other sites More sharing options...
Billggski Posted October 1, 2015 Share Posted October 1, 2015 The owners' club is actually that, one bloke doing for nothing in his spare time. No real connection with the manufacturer, more a fan club. The get together is at 10am on the 13 th at the NEC. Dethleffs themselves do a factory trip to southern Germany in May, they subsidise it and arrange a beer festival and trips on the lakes. But the owners club can arrange discounts for spares and technical advice, Dethleffs themselves are very approachable. Link to comment Share on other sites More sharing options...
jak Posted October 2, 2015 Author Share Posted October 2, 2015 If that's the case Bill then my comments are out of order although they were somewhat tongue in cheek. I may well make an effort to get upto the NEC. Link to comment Share on other sites More sharing options...
ken the kontiki Posted October 2, 2015 Share Posted October 2, 2015 Jak - I was trying to get hold of Carafax IDL99. By all accounts and web reviews, it's very cheap and importantly non-setting. As I was in a rush and needed something off the shelf, all my local caravan accessory shop (Salop Leisure) had was "Hodgson Seamseal CV" @ £7.00 for a 380ml tube. http://www.hodgsonsealants.com/product/10164/seamseal-cv-380ml-x-24. Having looked into the type of sealants used for re-sealing hatches, roof lights etc., all seem to recommend a butyl type product which Seamseal CV fits the bill. Edit - I cleaned up the surrounding surfaces with the wife's nail polish remover as couldn't find the 5lt of acetone I bought a while ago - doh :$ Link to comment Share on other sites More sharing options...
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