MatraSport Forum

Each model => Espace => Topic started by: Martin Tyas on April 24, 2014, 09:19:35 am

Title: Water ingress
Post by: Martin Tyas on April 24, 2014, 09:19:35 am
I'd hit a very large pot hole in the road, the presence of which was masked by it being full of water during heavy rain and although the rims, tyres and suspension were all fine on subsequent examination I'd heard a cracking sound from the roof as I'd hit the pot hole.
Subsequently I found that rain water was leaking into the vehicle and dripping off the head lining at the lowest point just in front of the rear view mirror.
Although I haven't yet had the screen out to determine for sure but it appears that the GRP roof panel has partially detached from the galvanised body shell along the front edge and water was getting under the windscreen trim and permeating into the roof.

As a temporary measure, until I can get opportunity to sort it properly, I taped over the windscreen trim creating a seal from the roof panel to the glass.... BUT.... when it rains I am still getting water coming in.
The only places that I can think that it can possibly be getting in is either from the roof rails or the roof gutter trim strip.

Has anyone ever removed the roof rails and if so was it evident that they could drain into the roof cavity?
Or has anyone every, for some obscure reason, had to remove the gutter trim strips? They appear to be attached using a double-sided tape as many items of trim are these days but it seems doubtful that there would be any holes in the GRP roof panel under that trim that could allow water in.
So at the moment I am completely baffled as to how water is getting in.


Title: Re: Water ingress
Post by: Valfrid on April 26, 2014, 11:50:20 pm
Might be worth checking the aerial - had this on old Renault 5's where eventually the seal would break allowing water into the vehicle. I had a new windscreen fitted on my Espace and the new seal they fitted was very poorly fitted with the double-sided tape just doing nothing to secure it but no water ever came in although the wind noise when driving at speed was exceptional! The other thought is - as you say, the actually glue seal for the windscreen has been compromised although depending on when you're screen was last replaced and the amount of sealant that is used for the windscreen, it should withstand a lot of abuse to the extent that usually a screen itself will crack before the seal that bonds it fails but there is always a first time...

Title: Re: Water ingress
Post by: Martin Tyas on April 29, 2014, 11:06:33 am
Thanks for all your ideas but I can comment as follows
  • the windscreen is the original factory fitted and so rules out any potential issue caused with the fitting of a new windscreen
  • I checked the aerial and also from the inside by removing the centre console in the roof panel and completely dry
  • I've since poured water just into the roof rails to see if was getting in through one of the fixing points and no water came in
  • I also poured water just into the gutters where the rubber strip is located and no water came in
  • I then poured water across the top of the windscreen where I'd applied the sealing tape and no water came in
But then if it's out in the rain for 10 minutes then water is starting to come in !!!

I know what you are saying that you'd expect the screen to crack first. However, with the way the Espace is constructed with a galvanised body shell to which is bonded the GRP panels, it may depend upon whether the screen is bonded to the galvanised body structure or the the GRP roof panel and having not had a screen out I don't know how it's fixed.

Whenever I'm on a rough or pot-holed road, and that now seems to be the majority in the UK, there is often a creaking noise from within the front roof area. So, whether the GRP roof panel has come adrift from the steel body shell or the screen bonding become detached from whatever it is fixed to (the GRP roof panel or to the galvanised steel shell) I am not sure and won't be until I have time to get the screen out. But in the meantime it just has me baffled how water can still be getting in

Title: Re: Water ingress
Post by: BrianM on April 30, 2014, 10:01:51 pm
I would remove the roof lining first, its easier & less expensive than removing the windscreen.

Title: Re: Water ingress
Post by: Martin Tyas on May 12, 2014, 12:28:32 pm
I had thought about that Brian.... but.... they never seem go back the same and whilst taking the screen out is a big enough issue because of having to remove the speakers, dashboard top, both mirrors, the wipers and the scuttle panel I wonder if the roof lining could be even more of a nightmare. The reason I say that is because the trim for both of the front screen to side screen pillars and both 'A' posts is sewn to the roof lining and so all 4 of them, and their inside trims have to be removed along with the main roof lining.

But in the meantime I have tried another temporary solution and removed the heavy duty cloth reinforced PVC tape that I had hoped would seal between the GRP roof panel to the windscreen and replaced it with 100mm wide Flashing Tape ~ for those outside of the UK it has a thin aluminium face with a bitumen back that is used mainly for roofing and guttering repairs.
At first I thought that it hadn't worked because the cloth that I wedged above the mirror to soak up the water coming in was still quite wet after all the rain we had during the weekend but I've kept changing it for dry cloths and this morning everything is dry so I think that initially it was water that was still in the roof area that continued seeping through.

Also I have been studying Section 54 of MR316ESPACE56_BODY-INTERIOUR.pdf in the Vault I believe that I have found the likely cause and it will require the screen to come out.
In that service bulletin there are a couple of diagrams ~ one has the caption 'Windscreen pillar' and the other 'Fitting the windscreen at the roof' but it has the diagrams the wrong way around. The diagram that is under the 'Windscreen pillar' caption should be under the 'Fitting the windscreen at the roof' and vice versa. I have downloaded the bulletin and then extracted the relevant page and attached it to this post for anyone interested and to avoid having to go to the Vault and trawl through a large number of pages.

Looking at the detail in the diagram only 'positioning stops' as they are described, or packers as they may be described in the UK, are between the screen and the GRP roof panel and the screen is bonded to the galvanised steel shell as you would expect.
So, after seemingly successfully preventing water getting between the GRP roof panel and the screen glass and after studying the diagrams I can only suggest that hitting the big pothole created sufficient torsional forces on the body shell to cause the adhesive bond across the top edge of the screen to either came away from the glass or the galvanised shell.

Title: Re: Water ingress
Post by: Martin Tyas on August 19, 2015, 01:00:09 pm
This summer I finally got around to sorting out the water ingress from above the windscreen.

Having got the original screen out the cause of the problem became apparent.
The screen was bonded perfectly across the bottom and up each side. It was also bonded perfectly to the paint across the top of the screen... it was just that the paint was no longer perfectly bonded to the galvanised body shell.
I've attached a photograph.

After the galvanising process it is usual to apply what is known as T-Wash, which is a modified zinc phosphate solution containing a small amount of copper salts but also comprising of phosphoric acid, methylated spirit and water. It is accepted to be the most effective method of preparing galvanised steel to produce a sound substrate for painting. However, it looks as though it may have 'pooled' in the small gutter above the screen and so the paint did not adhere as effectively as it should.
So I guess what happened is that the torsional forces on the body shell from hitting a large pot-hole in the road caused the paint to come adrift from the body shell leaving a small gap between the flaked paint and the body for water to get in.

If you look closely at the photograph it can be seen how badly the paint was flaking... and going right back under the GRP roof panel.


Title: Re: Water ingress
Post by: BrianM on August 20, 2015, 12:53:20 am
Very interesting. Thanks for the update, it's nice to know you got it sorted. I think we had a similar problem with one of ours. However a bead of 'tiger seal' along the top, under the rubber trim, cured it.