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Header rail question

Posted: Mon Dec 07, 2020 2:55 pm
by Allan T
This ought to be one of the easier questions ever asked - my header rail has two black plastic blocks, one fitted close to each end, measuring about 10 x 5 x 20 mm. They look as though they ought to fit either inside or outside the windscreen pillars, thereby centering the roof. But they don't fit inside or outside the pillars - the gap between the blocks means they can only be fitted with them sitting squarely on top of the pillars.

The roof looks too high, the side flaps are above the door window glass, and the short press-fastener straps at either side slope down towards their windscreen-end, thereby delivering rainwater onto the diver's and passenger's outer legs.

Is it the same for everyone, or have I got an eccentric roof?


Allan

Re: Header rail question

Posted: Mon Dec 07, 2020 4:23 pm
by Charles Farran
Allan,
I have just taken a picture of mine which may help. (Mine are as fitted in the factory as original roof).
Cheers
Charles

Re: Header rail question

Posted: Mon Dec 07, 2020 4:37 pm
by Allan T
Thanks Charles, that looks very like mine - even down to the colour! - but does yours leak?

I can't remember how previous header rails have 'sat', but I've never had a roof let in as much water as this one does, especially not pouring down the side straps so I need to have a towel over my leg.


Allan

Re: Header rail question

Posted: Mon Dec 07, 2020 5:45 pm
by Charles Farran
Hi Allan,

Many years ago when i used my car as a daily driver in all weathers , in torrential rain i would get water drips coming in from the top roughly in line towards the back of the quarter lights ( i guess the forward progress of the car pushed the rain back from the corners). I would also get one or two drips from the hood fastener area at the top of the screen which used to drip down and hit the crash rail nothing excessive but tiresome! At the time i just put up with it but used to fold a hanker-chief or something similar just under the quarter-light catches for the side issue to stop the water running down the door cards & making the carpet on the sills wet! I was always careful to ensure the rubber on the front header rail always sat on the top ledge of the screen without any getting trapped in on the edge - having experienced increased water ingress if i had been hasty / negligent. A few years ago i replaced the rubber seal that slides in to a groove of the header rail -If yours is short at the corners that will exacerbate water getting in.
Cheers,
Charles

Re: Header rail question

Posted: Mon Dec 07, 2020 7:04 pm
by Allan T
Thanks Charles.

Sounds as though I've had almost forty three years of consistent above average luck with two MGs and several replacement soft tops, and at last the law of averages has caught up with me!

Any other insights, anyone?

Re: Header rail question

Posted: Tue Dec 08, 2020 11:25 pm
by Allan T
I've bodged a workaround, by the way.

Since rain was running down the short strap fastening the roof to the top of the windscreen frame, I've unfastened the press-stud from the frame, and folded the strap up out of the way, behind the frame.

Re: Header rail question

Posted: Wed Dec 09, 2020 10:09 am
by Michael Barclay
Hello Allen
I had a look at my roof today and the blocks are in line with Ian’s pictures. My roof is the original one fitted by the factory (1974) and although no consolation to you, has never leaked even when driven back from Stoneleigh in Feb during storm Dennis. I’m not sure if your Header rail/roof has been replaced but the following might be of help.
The original rubber seal was showing its age and had become crusty and hard at the ends nearest the quarter-lights. When the rubber strip was removed I found the aluminum strip very distorted, probably from being compressed onto the screen frame over 40 + years of use. Interestingly, under the aluminum strip was some form grey sealant (Like a grey putty) so obvious the factory were aware of possible leak issues.
I purchased a new aluminum strip and rubber seal and some flexible caulking sealant from Frost. I began by putting a very thin bead on the back of the aluminum strip before pop riveting the strip in place. The rivets have to be an almost flush fit in the rail, particularly at the ends otherwise the rubber strip does not sit correctly. The first rubber strip purchased from a very well know supplier was useless. The profile was nothing like the original and would not fit into the aluminum rail. I ended up purchasing another 2 from different suppliers before I got one that gave a good fit.
The bolts on the clamps allow vertical movement while the captive nuts in the header rail provide some lateral movement of the header rail on the screen frame. When I initially checked I found the black plastic blocks were not sitting centrally on the screen pillars (they were over to the right) I found by not engaging the metal roof rail into the fixing on the rear deck this allowed it easier to adjust the front clamps to give a good fit between the header rail and screen. Used the car last week in the rain , no leaks.
Best regards
Mike Barclay