Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Stress cracked windscreen

It's my understanding that most crack from the top left corner diagonally down. Is it an MOT failure if the crack does not fall into the drivers field of view zone?

Good question the answer to which I am unaware !

Removing the screen would ensure a pass maybe

I'm sure someone will give us a steer on the Reg's before too long.

My take on cracked screens (and I suffered one a couple of years back, replaced under warranty) is that the heating element is the culprit weakening the laminated glass or causing a stress raiser - I have yet to hear of a stress cracked unheated screen.

I ran a 1994 +8 for four years until I replaced it with my 4/4 Sport in 2009 with no record of any replacement before or during my tenure. Considering the torsional forces at work on the body being transmitted through the body flexing onto the windscreen mounts of this considerably heavier car it makes one wonder what has gone wrong with the 4/4 Sport windscreen arrangement.

I believe Charles Morgans "Management Silence" when asked a direct and fair question during a recent factory visit regarding this matter speaks volumes.
Cynically it tells me his bean counters have been at work and provided him with the recall figures to fix the problem and he found it unacceptable unsurprisingly.
My cynicism is based on 43 years experience in an engineering environment which is always realistic albeit unpopular at times.

I have not heard of a Roadster screen cracking other than possibly yours, there have been an odd +4 but the Sport has a recurring problem as a few of us have found. For this reason I'm open minded about the heated screen theory as surely we would have had a few more failures on these other "heated" models possibly.

Only when I mentioned getting an Independent Engineers Report upon my 2nd failure did the Factory agree to replace the screen at my dealers instead of the Insurance route, this I believe was also telling a story in itself.

The replacement of the screen mounts for a more rigid construction is the clue I feel but time will reveal the truth if not Charles.

I would agree. I have had Mogs for 12 years & as both were pre 97 no screen problems.

I've had one crack from top to bottom on my 1972 4/4 about ten years ago. The insurance copped it.

my cracked screen was a 4/4 Sport with traditional chrome supports, the screen on my Roadster with cast brackets gave no trouble.

Richard, thank you for your answer. I assume the studs has nothing to do with it then.
As I have a heated screen (4/4 -99) with a couple of threads not working I wonder about the wiring: If it was one continuous loop it couldn't behave like that. If the vertical threads are all separate they must be connected somehow to a common 'bus' wire in both ends. Does anyone know and could it be a potential problem causing cracks?

I agree with those of you (above) who thinks it is.

My first 4/4 from june 2000 had heated windscreen wich never fails (47000 km).The windscreen of my 4/4 sport has been broken after 2000 km .It was repleaced under waranty by my dealer.They have said that is was not correctly mounted.Too much stress on
the bottom of the windscreen due to the leather wich is above the dashboard .They cut off a piece of the leather.

The crack was not aligned with any of the studs - but was about 1" away. The cracks did start in the corner - passenger side.