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MG MGB Technical - Windscreen seal gap

I'm restoring a 1969 MGB. Just replaced the original front windscreen, all seemed to go well. The problem I now have is that there is about 1/4 inch gap between the seal and the front panel (shroud) just behind the air vent slots. The rest of the seal, at the centre and posts fits tightly to the front panel. If I push the panel up from under the dash it does seal against the rubber but drops again when pressure is released.
Has anyone else had this problem and is there an easy fix?
All the seals are new.

Regards
D Beardsmore

I don't understand, you say it fits tightly at the centre, but not behind the air intake which is in the centre. New seals should come with a pronounced curl to the leading edge which means it is pressed down tightly on the panel when correctly fitted, so much so that it can be a problem getting the leading edge uncurled enough to get the frame fully seated into the body - see the attached image, new seal profile unfitted on the left, as fitted on the right. You have got the 'T' of the seal properly located in the channel in the bottom frame rail, haven't you? And the frame fully seated?

P Hunt

Paul,
Thanks for the reply. Yes, the seal is fitted correctly. The vents I refer to are the two inside screen air vents on both side of the panel - not the larger central one outside the car. The gaps between the seal and panel are in line with the wiper holes. The seal fits correctly in the middle and at the posts. It's almost like the panel has been bent down at these positions but the frame fitted fine before.

Regrads
D Beardsmore

Could it be that you've missed the proper holes to reinstall the windscreen? By that I mean, could you have bolted the bottom hole of the legs (of the frame) into the top holes of the car body? The windscreen is really hard to push down, hold, and get the bolts started correctly.

Wayne
Wayne Pearson

Wayne,
I can confirm that the windscreen is installed correctly.

The stiffness of the front weather flap on the seal is pushing the panel down to form the gap between the actial seal and panel. If I ease upwards the front weather flap a bit the seal does make contact with the panel but its not really pressing down very hard.

There is a packing plate under the centre of the frame, secured by two bolts. Could I remove this plate? is it important? This would allow the frame to be pulled down a bit closer to the shroud panel.

Regards
D Beardsmore

The flap is what makes the seal.It conforms to the cowl along it's forward edge.
Sandy
SANDY SANDERS

"This would allow the frame to be pulled down a bit closer to the shroud panel."

Highly unlikely I'd have thought, it is more likely to pull the middle of the panel up than bow that alloy extrusion down, unlesss the frame bolts are loose and it hasn't been pushed down as far as it needs to go. It sounds to more likely that the panel inside the car at least has been distorted into a wavy shape. Or is the centre bar over-tightened which could be bowing the lower frame member up? It only needs to be just nipped up, not cranked down.
P Hunt

You couldn't post a picture of the problem could you? It might be much easier to figure out what's wrong then. I remember fitting my screen on my roadster and there was no way there could be any gap underneath. It was very difficult to get it down low enough to get the bolts in. I ended up with my wife sitting on top of the frame with her feet on the bonnet just to force it down enough.
Mike Howlett

Much the same here, had to use a clamp each side plus two beefy blokes to pull it down far enough to get the bolts in with a new seal. With an old seal it just dropped straight in, but still no gaps on the inside or the outside the full width of the bottom seal.
P Hunt

This thread was discussed between 04/01/2010 and 06/01/2010

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