Body/Trim: Windscreen water ingress

[Jungle_Jim]

Hi folks

This is getting ridiculous... it's been very rainy as we all know, but, my 240 has a lot of water ingress behind the dashboard and it's wreaking havoc with the electrics. Ironically it's the windscreen wiper circuits which are going haywire (those badly positioned relays - but this thread is not about that).

The other day there was a line of water making its way down the plastic next to the fuses.

The question here is - can I assume it's the windscreen seal, and if so what are my options:
(It's a 92 model with the later flush-fitting windscreen rubber.)

1 - A 'just get by' fix?
Would it be worth it to get some black sealant, and fill up the space behind the rubber between the glass and the window frame with copious and continuous sealant? And if so - what sealant would be recommended?

2 - the 'proper' fix?
A new rubber? Re-bond the screen?

My car has a factory sun-roof, which has its own occasional drips, but I don't think that's the source of the water behind and below the dashboard.

Thanks
John

[Clifford Pope]

There are several favourite means of water entry:

1) As you say, between the glass and the lop of the metal frame on the inside.
I used black mastic gutter sealant - very sticky, works on damp surfaces, cohesive enough to squeeze nicely but has a fibrous quality to hold together. I rammed it down on the inside after removing the plasic trim, using the blunt end of a pencil

2) From the grommet round the windscreen wiper spindle - not the outer one, the inner one you can see behind the glove box.

3) Blocked cill drains causing water to accumulate in the cills and splash upwards in the space inside the door frame and dribble down over the fuses.

4) Rusted door frame allowing water access behind the fuses

5) Missing or damaged waxed paper seal over the apertures in the frame where the fuse box fits.

[Bob Meadows]

https://www.ebay.co.uk/itm/Windscree...oAAOSwT5ZfyPs6

This sealant works well- leave in hot water for a while if cold etc:~

I have the same problem on the drivers side (small leak) see other post but on the list for later in Jan/Feb.
Most points have been covered regarding checks etc but a couple of things that I've also done prior to removing the window trim is to check the rubber grommet just below the door hinge- this is fitted from the inside of the "A" post and has a dished section that should be clear of any debris, sealed mine with Waxoyl.
Check the seal for the rubber boots that cover the body-door wiring.
Check the dashboard fixings bolt to the "A" post ie the inner bolt at the top of the waxed paper/cardboard seal behind the kick plate- also check the seals for the ventilation door on the above. You should also find a bolt on the outside of the "A" post that should also be sealed (dashboard bolt) - may be worth checking the door hinges into the same post.
The bonnet pull seal into the bulkhead can also allow water in (so I believe)
Wiper motor should be sealed with Dum-Dum for the passenger side.
Door seal rubbers ok?
The above applies to the '88 240 estate.
Regards Bob.

[DW42]

I had the same issue with my '92. It was only a small leak, but a small leak plus monsoon = one soggy carpet. I had a windscreen fitter come to my house and refit the original windscreen. Luckily there was no rust around it, and he didn't break the windscreen when removing it (he made sure there was a new one at the supplier before he did the work). No problems since. It's worth getting this done properly, given the electrical nightmares which can ensue.

[Jungle_Jim]

Thanks for these suggestions.

I will try first with a seal like the one Bob recommended - much appreciated - and hope I can stop the leakage cheaply.

One other question - while we're on the subject of this: There is also water ingress coming in around the tailgate hinges. This is made worse on my car because, due to sag in the hinges, I have had to use penny washers to lift the hinge up so the tailgate fits better. But this has caused gaps because the hinge is no longer compressed against the rubber seal to the roof (there is gutter sealant in the gap, but it's not doing the job).

When you say 'dum dum' - is that the stuff that comes in strips that you can form a bit like plasticine or blu-tak? As opposed to caulking gun tube stuff? For sealing the hinges, I'll need something that can hold its shape and fill a gap of 1-3mm.

Thanks again
John

[Clifford Pope]

I'd cut an exact gasket out of a bit of aluminium sheet, and then use gasket sealant on both sides.

[Burdekin]

Never used it on a windscreen myself but this is good stuff at fixing wee leaks and might be a good temporary fix for you: https://www.ebay.co.uk/i/12446489670...RoCziEQAvD_BwE

[Bob Meadows]

John:~
Unfortunately Dum-Dum is no longer available (I have a half tin left from the 70s that is used on the Riley) the original was a little like oily putty but doesn't fully harden only forming a slight skin-- the product is used on the 240 in places and can be retrieved for further use.
The screen seal that is recommended has been experimented with and if extruded onto a clean surface allowing the oils to evaporate then it takes on the consistency of Dum/Dum but not as good. Mastics in other forms are also available for classic cars.
Regarding the tailgate hinges- the original rubber gasket is shaped to lip the chrome edges & into the screw fixing holes.
The washers have probably disturbed the seal/lifted the hinge, the screen seal could also be used here so may be worth trying-just loosen the fasteners holding the hinges to the body and prop up the tailgate, extrude the sealant between body & gasket plus gasket & hinge (ie top and bottom of gasket) do both sides and fasten the tailgate back once lined up.
This will be a little messy as the sealant gets pushed out but it is easily cleaned up with a blunt scraper & white spirit- edges shaped to seal etc.
An alternative is to remake the gasket (the hinges are available new but I'm not sure about the gasket) gasket material is available form the likes of ebay- as mentioned the shape of this would be difficult to make- originals are descent rubber and should be ok if sealed as above.
I used this method when replacing the tailgate wires and to date it's been fine.
Regards Bob.

[Clifford Pope]

Originally Posted by Burdekin

Never used it on a windscreen myself but this is good stuff at fixing wee leaks and might be a good temporary fix for you:

I've used something like it - Findaleak or Stop leak ? and found it very good for the kind of irritating leak that tracks down a crack sometimes a long way.
The thing is you don't have to find exactly where it is or where it goes, this stuff flows down the crack (preferably dried first) and then semi-sets as a sticky gel.

I have made my own substitute on occasions, in larger quantities, by diluting domestic varnish with white spirit. I once treated an entire windscreen rubber with it. The rubber had turned porous and was just weeping lots of water but all over, no clear gaps. I made up the mixture in a jam jar and painted it on copiously, watching it soaking in until the rubber was saturated, then wiped off the surplus and left it.
I happened to have an old pot of matt varnish, and it was a perfect fix at no cost. As a bonus it rejuvenated the rubber surround, turning the grey rather friable surface into smart black.

It's similar in principle to the stuff you get for mending furniture joints. That's only diluted PVA really, injected with an old syringe.