Mystery Roof Leak

I have discovered a slight but persistent leak, which only seems to exhibit itself when I open the drivers door, letting a few drops onto the the side of drivers seat. At first, I just assumed that it was perhaps just a design issue, like the boot lid that lets in water when it's wet and opened. But I failed to notice the passenger door letting water fall on the seat.

Recently, whilst sitting in the car, I noticed that the internal seal at the rear section of the top roof panel was wet. When I prodded it a few drops of water would fall. Nothing much, but more than simple condensation I think.

One of the first jobs I did after buying the car a month ago was clean and treat the rubber seals all round in a bid to reduced creaks and rattles. That's not been entirely successful, so I will go over the seals again. The water could be coming in through the door glass/rubber seal interface. My gut feeling is that this isn't the source, but I could be wrong.

What intrigues me though is how the black metal edging strip that runs down each side of the roof is attached. And how does it contribute towards water tightness? Because it seems to me that water can easily pass between the roof panel and the black strip, so the water tight seal must be somewhere under this strip.

Earlier today I removed the roof clamp and roof facia panel that covers up some of the internal roof seal in the hope that something would be revealed. But I couldn't see how to proceed further without the risk of damaging the rubber. And at each end of the roof side-seal assembly there were two small plastic caps that probably covered screws, but I couldn't prise them off without risk of damage. I also noticed that some of the roof seal seems to have been finished off with glue. I don't know how essential glue is in making the whole thing water tight (I really hope it's only a cosmetic finishing thing).

Has anybody ever stripped these side roof seals down to understand what's involved in the design? I'm waiting for a bottle of Captain Tolley's Creeping Crack Cure solution to be delivered. Depending on the weather conditions required for that to work, I may resort to simply feeding a few doses of the Captain's best down the roof/black strip joint, in the hope that it will cure the leak, but not knowing precisely where the water ingress is coming in makes this a shot in the dark.

If anyone has any further suggestions, I'd be very grateful.

On the plus side, today I figured out how to remove the perspex wind deflector by only unclipping the side brackets, which I didn't know about before. No unscrewing, forcing or breaking is necessary. Only two small screw drivers to unclip the base of the top retaining cap from the main mounting bracket. Then the deflector easily pops out.

 

After another wet night, I had a good opportunity to examine the extent of the water ingress. As you can see in the photo there is water on the inside of the side roof seal and it's all along the seal. The photo
shows the front edge.

Has anyone had this sort of leak? And does anyone know how to detach this seal for further examination?

Thanks.

 

In between the incessant downpours and showers I have been able to part lower the roof, which actually increases the roof height and accessibility. I was able to remove the thick rubber seal above the drivers door. This required removing the most stubborn plastic stud at the front of the seal, then easing it out of a retaining channel. It's also retained by semi permanent black bitumen sealant (or black silicone seal. Difficult to tell - some was still sticky, some had skinned and dried). Most of this sealant hadn't bonded with the rubber seal, but I don't think that is the cause of the leak.

With the rubber seal hanging off at the back, the metal roof edging strip was more clearly revealed, being composed of stainless steel and a black coloured metal, seemingly held in place by 4 screws. But removing the screws didn't result in the edging strip becoming removable. It seemed as solidly stuck as with the screws fitted.

I will post photo's below, but my observations suggested the following:
* Previous to disassembling the roof seal I stuck gaffer tape along the length of the black facia strip where it meets the roof. This stopped the leak, so I know that the cause is something behind this facia strip and the rubber seal.
* The black facia strip doesn't seem to be designed to be water proof. So water easily creeps behind this strip.
* From the front, looking down the length of this strip and behind the facia strip reveals what look like a small drainage channel. But being only a few mm high, any water may then creep into the seam between this edging strip and the main roof structure.
* I can only speculate that this edging strip must be bonded onto the roof structure, because removing the 4 screws didn't allow for any movement. This bonding has probably failed to allow water ingress. I cannot remove the strip without fear of damage. It's thin metal and it's integrity would be further compromised if the strip became kinked. Nor can I see an easy way of applying sealant directly to the hidden seam where the breach is.

My only option for now would be to attempt to squeeze silicone sealant into the gap between the facia strip and the roof. Unless anyone else could suggest something better?

 

Water is easily draining between the black facia strip and the roof. The peeled back rubber seal reveals the stainless steel profile which interlocks with the seal and holds it in place

 

OK, I've decided that as I'm not going to attempt to detach the edging strip, I'm going to apply silicone sealant, first of all where the main rubber seal is locked onto the SS profile. The original silicone application here looked bad, not adhering to the rubber. Whether a better application will improve things, I don't know. Second application will be from the underside (inside the cabin). There is a 5mm gap between the roof panel and the SS profile. I'm going to try and fill this in. Thirdly, I may consider filling the outside gap between facia and roof panel. Will probably leave this until I've seen the results of the other two applications of silicone.

 

Leaking seals may well be old rubber, so it's important to revitalise them with something like 303 Aerospace 303 Aerospace Protectant - 10oz - Protects Car Vinyl, Rubber, Plastic, Leather 82043303089 | eBay

On the subject of my Copen's leaking roof, I should have updated the thread, because it did not end well attempting to fill the void behind the 'drip rail'. I wanted to fill the whole void up but instead only filled in the ends, with much sealant squeezing out onto the roof and not eneough along the length of the roof. Not good at all.

So I decided I needed to get the rubber/steel profile strip off completely to get to the root of the problem. With the main outer seal removed along the length of the roof, four screws are revealed, locating the steel strip on the roof - remove those.

There is a black sealant that does the job of waterproofing and keeping the profile strip intact (the screws are there more to compress the sealant than providing strength to the joint). I chickened out of breaking this joint the first time I looked at this leak, because I was nervous about distorting the steel profile and messing it up. Well it turns out that some careful levering does separate the joint with no damage. Starting at the front end of the strip, I used an old butter knife (which is ideal, being wide, thin and without a sharp edge) to get in between the strip and the roof. You could use a large pen knife blade, but not having to worry about a sharp edge should the knife slip meant I could concentrate on the job in hand rather than avoiding injury to me or the car.

Once the first couple of inches are free, then the main work is to slide the knife in from under the strip and work at slicing the sealant without pulling at the steel strip if possible. Work progressed pretty quickly and upon removing the strip it was apparent that the sealant applied in the factory may have been a bit too sparing to make a good seal.

All the old sealant needs removing and and a genuine citrus solvent cleaner like the cycle brand Finishline does dissolve the sealant. Finish Line Citrus BioSolvent Degreaser

It's a bit of work removing it, but it means the new sealant will go on evenly. Genuine citrus cleaner smells of fresh oranges and feels like white spirit, the cheap stuff smells of orange squash and feels more like soap.

Now to reattach the profile strip. I replaced the original rusty screws with some button head stainless screws just because It had them. It doesn't really matter though, because the steel screws locate in plastic nutserts, so there's no danger of galvanic corrosion with the alu roof.

My preferred sealant of choice is Geocel Trade Mate roofer's sealant, because it only semi cures. It adheres very well, but allows for some movement, potentially self healing, where a silicone sealant has less give and might pull away. So it's good for any sealing job and allows for easy disassembly for future inspection and reapplication if it should prove necessary. I reckon Diahatsu use something similar, because it definitely wasn't as silicone sealant and had the same semi cured properties. They just didn't use eneough!
https://www.screwfix.com/p/geocel-t...6GEzgP5JBjbv8r_4-a8aAgN-EALw_wcB&gclsrc=aw.ds

Needless to say I applied a fatter bead of sealant than the factory did and located the strip with the four compression screws. Tighten the screws but do apply equal pressure along the whole strip. Then reassemble the outer seal and the job is done and should be instantly waterproof.

Sorry no photo's, but if I can answer questions if I appear to have missed anything out.

Hope that helps!