Ant,
I have exactly the same problem on my 2015 Bav 41. Can you tell me what you did to fix the problem?
many thanks
Chris
Hi Chris.
As we said this is a known problem, unfortunately Bavaria and their franchise's will not admit it or will keep doing bodge repairs until you give up or live with it.
The problem;
Mastic/sealant joints cannot be pushed or pulled in two planes. IE left right and in out. As the windows expand at a different rate to the cabin top the differential in thermal expansion causes the Mastic /sealant to pull away from one /both of the window edges and also the cabin top between the windows.
In addition Bavaria used a fixing to pull in the window(s) back to the cabin top during production. The fixing creates a hole in the cabin top about 100mm from the base of the window.
When the fixing is removed in production it is not filled with gel coat, just left.
Remedy;
Carefully remove the Mastic /sealant between the windows, cutting back to the gel coat and removing all traces of the sealant. If your careful you can use scotch brite green to abrade it away. Do not over do it and use the scotch brite on the face of the windows. A wooden scraper can be useful for this too. DO NOT USE ACETONE!!!
When the area is cleaned and all the Mastic & Sealant is removed fill the fixing hole with gel coat filler. Cover the gel coat with peal ply or you can use masking tape. `If not you will need to over fill and sand back the filled area.
Add a strip of bond breaker tape over the affected cabin top. This will be an area roughly 20mm by 200mm. Bond breaker tape from Ebay or a good glazing supplies. If not, you can use a non adhesive strip of plastic or polythene and apply this.
You only need to apply it in the area between the windows +2-3mm If your using the latter just lick the first and last 5mm to hold it in place temp. (old facade trick).
Get the Sika product and the primer from Sika in Welwyn Garden City in Hertfordshire England. (There is a how to video they did at the boat show that is really good on YouTube)
You absolutely must use the primer! Or the joint will fail.
Taking your time fill the gap having primed the area along the window sides. Try to avoid primer and sealant on the bond breaker strip.
Tool the product smooth and flush using a silicone squeegee, or a used credit card dipped in soapy water. Level with the window faces. And flush with the existing fillet at the top and bottom of the window.
Cover the area for 48 hours to protect the area from direct sun light.
When the sealant has cured and is firm to the touch, rub your finger over the surface to give it the same appearance as the existing seal.
It will not leak again because the sealant is only being pulled left and right and is not bonded to the area between IE is free to move on the bond breaker. Meanwhile the hole will not let in any water even if the seal fails between. As its now filled.
Hope this helps. If you need any more info PM us and we can talk you through the problem.
Dont forget we have a YouTube channel. Over the winter we will be doing some how too's and maintenance tips.
Ant & Cid xx