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MG Midget and Sprite Technical - Windshield Frame Bottom Screws

Hello:

Now replacing the rubber bits & pieces on my 1972 MG Midget windscreen - and after removing the rubber trim between the frame and body cowl - I can see TWO screws on each end.

Can anyone confirm that they are either Posidrive or Phillips #2 (or similar...)

The screws must have been removed in the past - and the screw heads are somewhat beat up on the other side and one of them is standing "proud" in the aluminum channel preventing the "feeding" of the new replacement rubber seal, etc.

Also, I have heard that over driving them can actually stress and crack new windshield glass - so I am trying to remove them and file the screw length down a bit to prevent that adverse event occurring upon completion of my project...

Thought & comments appreciated...

Mike
Buffalo, NY
USA
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Mike Pelone

Hi Mike,
yes they're either Pozi or Phillips, *IF* (please check) they're the ones listed by Moss as CMZ305 then Paul's list has them as "CMZ305 - SCREW, CROSS HEAD, CSK, ZINC, UNF, NO.10 X 5/16".

I've just looked and the ones fitted to the top rail of my refurbished windscreen are Pozidriv but that doesn't mean they're correct.

I've also heard that the screw lengths are critical to prevent glass damage.

Links -
http://www.moss-europe.co.uk/windscreen-fittings-sprite-iv-midget-iii-1500cc.html

http://www.mgb-stuff.org.uk/partnos.htm

http://en.wikipedia.org/wiki/List_of_screw_drives
Nigel Atkins

Mike

Looks like a pozi-drive countersunk set screw:

http://www.northwestimportparts.com/MG-Midget-Windshield-screw,-short-64-79-d2368.aspx

https://www.rimmerbros.co.uk/Item--i-CMZ305

http://www.leacyclassics.com/cmz305.html

Cheers
Mike

M Wood

To shed more light onto this issue, I did order various screws from Victoria British for comparison.

It is somewhat strange that on the top frame section – the outer most screw (both left side and right side) have different part numbers than the inner set of two screw (also left and right) – but that may explain either length or drive style of the screw hardware.

On the underside of the aluminum frame, Vic British catalog shows the following:
Lower frame Side
Figure #12 – 4 inner
Figure #13 – 4 outer

Conclusion: Four positions and four part numbers

In contrast, Moss USA shows a difference between Upper Frame side (both inner 4 screws & outer 2 screws)
While the bottom side indicates that the corner bracket is NA (no available) and the bottom rail bracket attaching screws are also NA. The Good News is that the 4 screws required between the pillar and the bracket can be ordered.

Conclusion: Variations between Moss & Vic British catalog prevents a final determination as to correct size and screw type - I believe that the Vic British must be making some type of “substitution” as to screw size and/or type. That may explain why some screw locations on my frame appear to have Phillips screws where Posidrive screws should be located.

I am off to the hardware store to purchase a set of Posidrive tools and see how much force is required to remove the old hardware.

Worse Case alternative is to use a Dremel tool and grind down (selectively) any screw heads preventing the rubber sealing strip from moving along the channel in the aluminum frame…

Thanks for the comments & part numbers…

Mike


Mike Pelone

Good luck with removing the screws. They can be well rusted.
Dave O'Neill 2

You can tell the difference by the marking on the head. Posi has a thin cross mark between the main cross. I would have said they were Philips originally but could have been replaced by Posi over the years as that is what most seem to be now, but I was surprised to see that Posi were in fact invented in the mid fifties. I thought they were much later than that.

Trev
T Mason

It is possible to renew the rubber seal between screen and body without dismantling the frame. Plenty of elbow grease and Fairy liquid.
I've left the original rubber between screen and glass as it was a lot easier and it hasn't perished/failed as yet.
Suspect you'll need the patience of Job to shift those screws :)
Jeremy MkIII

Maybe one will come out easily. Then you can take it down to the tool shop and try all the screwdrivers till you get the perfect one. That's what I do.
Nick and Cherry Scoop

Penetrating oil - not WD40 - repeatedly over a few days and leave. Try an impact driver, carefully and gently

Mike
M Wood

If someone's already b*ggered up (a technical term) the screw heads then the previously correct screwdriver may not be the best type to use. I was going to post a photo of no.2 Phillips and Pozidriv screwdrivers but as the article said it's difficult to see the difference between the two especially in a static photo.

Personally, if possible, I'd leave the screws and buy some silicone oil (not the thin spray but oil - or perhaps silicone grease if you have it) and use that to get the rubber seal over the screw heads.

I bought individual Pozidriv and Phillips screwdrivers as "bottom drawer" items nearly 40 years ago and I've very rarely used the Phillips especially no. 3 and 4 which I can't ever remember using on anything. I have used no. 3 and 4 Pozidriv on my Midget though but the screws weren't necessarily original items.


Nigel Atkins

An Update on the Final Solution...

Removed the left side part of the aluminum windshield frame using soft wood block and rubber hammer - purchased a tube of silicone rubber grease - then installed bottom rubber seal side ways...

Looks to be original rubber gasket around glass - observed some type of plumbers putty inside channel of aluminum frame channel - don't know why that was there - plan on reinstalling metal frame tonight. Do not plan on adding any type of silicone sealing "magic" goo...

Definitely beats hand feeding (and bending..) the 48 inch rubber seal into the grooved channel using a putty knife and/or plastic "spudger" tool.

Might need to use a ratchet strap to hold unit together while installing top and bottom machine screws...

Purchased a 4 piece Pozi Drive screwdriver set - this tool set was surprisingly hard to find even on the Internet...

Always a good ending when you get the job done AND add a few new items to the tool box...

Mike
Buffalo, NY
USA
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Mike Pelone

Well done on sorting it.

I do increasingly find Google particularly difficult to shop with if you want something slightly off fashion and just tried a search for a set of Pozidriv only without result.

I'm not sure how much information is being lost or totally submerged by the use of the internet.

Over here you can walk into most brick and mortar DIY shops and pick up a single screwdriver or mixed sets but getting sets including no.3 and no.4 Pozidriv would be much more difficult.
Nigel Atkins

This thread was discussed between 19/08/2017 and 23/08/2017

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