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SP250 windscreen rebuild

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heh101353
Posts: 55
Joined: Sat Sep 30, 2017 11:34 am
Location: Basel, Switzerland
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SP250 windscreen rebuild

Post by heh101353 »

Experts needed ...

I have to replace my windshield because it shows too many scratches and under rain or bright sunlight it may blur the vision. At the last Swiss MOT they already put a notice …

First a simple jig to indicate the angle the refurbished windshield should sit at after re-assembly.
Image

While undoing the nuts under the dashboard it turned out that the 1/2” box spanner was very tight.
Box spanner metric 13 was okay though ???
Next surprise was with the shouldered bolts at both ends of the windshield. No shouldered bolts to be found.
Just a nut, a really large washer (could not be removed through the hole in the body, had to remove the trim panel)
and a bolt protruding from the top into the body to tighten it down. Box spanner metric 13 here as well???

With the windshield removed and on the workbench the whole mess revealed itself.
Image

The frame held together by a plethora of different screws of different length, diameter and head types,
screws missing, joint pieces tapped to bigger diameter screws which leaves the sides of the frame having just a tiny bit of material left, ...


Top right
Image

Top left
Image

Top left separated
Image

The left and right parts of the frame have been drilled to accommodate the M8 bolts.
Image

Bottom right
Image

Bottom right separated
Image

Bottom left
Image

Bottom left separated
Image

Somebody in the past used M8 bolts and nuts to tighten the thing down to the body
M8 at bottom left, joint pieces obviously “home made”.
Image

Ordered a rebuild kit from BT (joint pieces and small screws only)
Image

Now this looks all fine but I’m a bit at a loss on how to tap the new joint pieces.
Thread type, drill through, not to drill through.
Reinstalling/reusing the shouldered bolts at both ends of the frame, …

Any help most welcome.
Especially if somebody has some pics of tapped joint pieces and would post ‘em here would be very nice.

Thanks to everybody for your kind assistance
Hans
Owner since 2015 :mrgreen:
http://www.wyhe.ch/

grahamemmett
Posts: 761
Joined: Mon Feb 08, 2016 8:12 pm
Location: Northwich, Cheshire
Contact:

Re: SP250 windscreen rebuild

Post by grahamemmett »

Do you know what a UK garage would say to that... ?

"That's buggered that mate"

Anyway, you've until May to sort it out, can't miss Spa! Have you tried Christian Demler?
Graham Emmett
Northwich, Cheshire
Joint DB18 Registrar (with Marcel Renshaw)
DB18 1949 LCV522 (Yes that one with the P100s)
https://www.db18.org

Patersoncm
Posts: 14
Joined: Sat Feb 13, 2016 1:20 pm
Location: Rugby

Re: SP250 windscreen rebuild

Post by Patersoncm »

Hello Hans

Not sure I can help much re your windscreen however I note that you live in Basel. My son moved to Basel about a year ago ( Reinach) and I have owned my SP250 since 1972. It may be good to meet up? Over the years I have tackled most things including rebuilding the windscreen and am now into a major classic off rebuild. I will be visiting my son in early March.

Cheers



Chris

Ian Slade
Posts: 504
Joined: Sat Feb 13, 2016 9:54 am
Location: Akrotiri Cyprus

Re: SP250 windscreen rebuild

Post by Ian Slade »

Your windscreen seems to be a Mk2 my 1960/61 SP had a different construction arrangement though the actual frame sections are the same as the later screens my C spec has. The countersunk screws are/were 1/8 UNC they suffered from rusting and seizing, requiring drilling out, if possible it would be advisable to replace the steel jointing bars with stainless steel, if the holes are oversized and re tapped I would suggest using helicoils of a size appropriate to the over tapped size and fixed in place with Threadlock or similar, this will ensure that when the replacement screws are fitted they will not attempt to strip the thin threaded part of the frame
Owner since the 70's, Genghis is slightly to my left.

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heh101353
Posts: 55
Joined: Sat Sep 30, 2017 11:34 am
Location: Basel, Switzerland
Contact:

Re: SP250 windscreen rebuild

Post by heh101353 »

Ian,

thanks for your comments.
I'm still a newbie to the SP, so what do you mean by:
Your windscreen seems to be a Mk2

The screws I received from Barry look like No.10-24 UNC.
But with all the oversized drilling and metric threads found on the frame I guess I'm best off to use the new joint pieces with metric, stainless steel, countersink screws.
Another advantage: I don't need to buy UNC tapping tools. :lol:

Unfortunately my SP is more or less a mix of UNC, UNF, Metric, ... anyway.
Doing a suspension rebuild two years ago we found a lot of metric bolts. We reverted everything back to original standards.
But with this windscreen frame business I tend to make life not more complicated than necessary.

Thanks to all
Hans
Owner since 2015 :mrgreen:
http://www.wyhe.ch/

Ian Slade
Posts: 504
Joined: Sat Feb 13, 2016 9:54 am
Location: Akrotiri Cyprus

Re: SP250 windscreen rebuild

Post by Ian Slade »

Though the windscreens look the same the actual construction is different, on the Mk2 as yours is there is more machining and extra steel bars holding it together, the original screen was not as rigid and flexed at the joints.
Regarding the bracing template you have manufactured, just ignore it, the SP windscreen will pick up different angles depending whether a hard top or a hood is fitted, this requires the front guide for the side windows to be adjusted to suit the screen angle, apart from creating gaps allowing water ingress the foam seal glued to the side of the screen is easily damaged. The screen is normally pulled into the car at the top when the hood is up but pushed forward with the hard top.
Owner since the 70's, Genghis is slightly to my left.

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heh101353
Posts: 55
Joined: Sat Sep 30, 2017 11:34 am
Location: Basel, Switzerland
Contact:

Re: SP250 windscreen rebuild

Post by heh101353 »

Thanks Ian,

I guess I got it.
Mk2 refers to a "second generation windshield frame construction".
Albeit the overall parameters, like curvature and so on did not change.

Always a pleasure to learn ...

Thanks again
Hans
Owner since 2015 :mrgreen:
http://www.wyhe.ch/

DaveM
Posts: 29
Joined: Thu Oct 27, 2016 3:36 pm
Location: Haslemere, UK

Re: SP250 windscreen rebuild

Post by DaveM »

Hans,

Here are a few pictures to show what the connectors look like once drilled and tapped.
Sept 2017CIMG0001.JPG
Sept 2017CIMG0002.JPG
Sept 2017CIMG0004.JPG
One other piece of advice would be, measure the top cross bar and find the centre then mark the centre position with masking tape. Do the same for the bottom cross bar, finally measure the windscreen (string is good to use due to the curvature) and again mark the centre position of the screen. Now when you assemble, top and bottom bars first lined up with the marks then use ratchet straps to pull the sides on and it all should come together square. sorry no pictures of this

Cheers Dave

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heh101353
Posts: 55
Joined: Sat Sep 30, 2017 11:34 am
Location: Basel, Switzerland
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Re: SP250 windscreen rebuild

Post by heh101353 »

Dave,

thanks so much for the piccies. Very helpful.
I could go green with envy looking at that perfect upper bar. :mrgreen:
Mine looks a bit tatty but overall it's okay.
My vertical bars and the lower bar have been violated by some "drill and tapping expert". Unbelievable!

Thanks as well for the clever hint of marking the center to get the large pieces together in one go without risking to pull them apart again as the uprights will not fit because the screen is a bit off center.

Very much appreciated.
Hans
Owner since 2015 :mrgreen:
http://www.wyhe.ch/

Ian Hastings
Posts: 114
Joined: Tue Mar 15, 2016 3:00 pm

Re: SP250 windscreen rebuild

Post by Ian Hastings »

Check with Barry Thorne about the screws, if I remember correctly the originals were BA thread, although I could be wrong.

Also when assembling the screen, do the frame first without the glass in to make sure it ALL goes together correctly at the same time!

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