Sealing leaky bonded windscreen with 3M 08509

[berni29]

Hello again

My bonded (or at least it should be) +2s windscreen leaks a bit in one corner. At least the water ends up there. Who knows where it is reaaaallly leaking? I have looked into various sealant options and this one by 3M (code 08509) looks like the best. It never dries and you pump it up behind the surround (or under the rubber for those lucky people with rubbers). Wipes off the paintwork with a rag, and you can use it even if the surfaces are wet. Apparently. This is 3M's description..

Non-hardening, pliable, water-resistant, medium-bodied sealer for sealing auto seams and between windshield rubber and car body. Can be used as a supplementary sealer for auto glass installation.

Any non bonding sealant that dries such as silicone rubber always seems to end up pulling away from the edge and leaking again. I will let you know if this 3M stuff works as I will be using it tomorrow and then jet wash testing.

[niallf]

Hi Berni,

Where did you get the 3M stuff? My screen leaks like a sieve too !

Niall

[Elanintheforest]

Does anyone know how simple it is to convert from bonded to rubber seal? Is the glass bigger on the bonded screen or the opening smaller, as I guess that the bonded screen sits 'on' the shell, and the rubber seal screen sits 'in' the shell? It seems that so many Plus 2s suffer from this malady, yet I've never heard of a problem with metal cars....something to do with fibreglass moving / expanding & contracting maybe?

I have to replace a screen and rather fancy going old fashioned!
Mark

[niallf]

It's difficult, I think. The lips around the window for the two types of seal are different, as you suggest.

Niall

[ppnelan]

I too have a poorly installed bonded windscreen. It has a visible gap (!) down the driver's side (of course...). I thought I had sealed it all up, using translucent silicone sealant, but it leaked in the strong winds & rain on the way to Stoneleigh....

I understand that the fibreglass opening is smaller on the bonded cars to allow the special seal to be fitted, so I assume that, in principle, it could be enlarged to fit the earlier type. Perhaps someone else has tried it ?

Is it a DIY job to fit a new bonded screen ? If so, where do you get the sticky part of the seal from (the 'chrome' plastic part is available from PMS & probably others) ?

Matthew

[nebogipfel]

Berni, I would have thought the best option would be to (preferably) remove the screen and then bond it in properly with the screen bonder modern screens are fitted with.

It is strong and will gap fill well.
I bought a couple of tubes from my local mobile screen fitter.

I don't think a non drying sealant will be any good, they are really used to seal up rubbered in screens Silicone sealants are next to useless.

[berni29]

Hi John

Yes, you are right, that would be the best option, but I am nowhere near taking the screen out at the moment!.

I did have a go with the 3M stuff and got it everywhere except in my eyes. It does work because the car did not leak afterwards, but you have to get good amounts of it well under the surround. Maybe I should mask it up and pump in from the top. More experimentation required. At least the stuff can be cleaned off with tar remover.

I have an early and late bodyshell both with windscreens out and I reckon that it would be hard work modifying the later body to take early style rubbers, although people have modified rubbers and done it before apparently.

The only thing that I like about the bonded screen is that it must give the bodyshell some extra rigidity. Assuming that it has not been put in with bath sealant that is. One of mine was, and it made for very easy removal and left a nice surface for a proper job later.

Berni

[nebogipfel]

Berni, I've never really looked but I suspect the easiest way to convert a +2 to the early screen would be to graft the screen aperture from an early shell onto the car.

Much nicer than a stuck in one in my opinion. Apart from anything else it would enable you to throw the ugly trim moulding away.