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MG MGB Technical - Windscreen installation - What comes first?

Hi everyone,

Bit of a 'chicken and the egg' question here.

It's been a while, but I am now installing my reassembled windscreen on my 67B roadster. It's been off the car for about 2 years. My question relates to what you should install first... The windscreen or the door frames/quarterlights?

The reason I ask is that my B has had most of the body rebuilt, and there has been some movement in panels (it was totally out of alighment before rebuild).

I understand that in the installation of the windscreen and door frames, there is some room for adjustment so that they meet snugly when closed.

Is this 'adjustment' from the fitting of which component? My suspicion is that the windscreen is a 'fixed item' with no play in it. And that the doors are what is used for any adjustment.

From your experience, can you confirm this for me?

Also, how tight/snug should they be when closed?


Thanks,
I look forward to hearing from you all

Mark
M C Duggan

Mark,

You are correct. There is little to no adjustment in the windscreen. Adjust from the quaterlight. Snugness/tightness is the finesse! Too tight and the quarterlight will bow out and also make door closing difficult. Too loose, and there will be leaks and drafts. On my car, due to forces beyond my control, they are always a little too tight and I smear a tad of silicone grease on the gasket for easier closing.

Cheers,

Paul
Paul Hanley

I agree, the windshield should come first. After that bit of fun, the quarterlights will seem easy!

When you adjust the doors, you'll know if you have them right or not. Its the "feel" that you're trying to achieve as well as the gap/clearance.
Jeff
Jeff Schlemmer

Oops, I would advise that adjustment must be done moving all components. With the screen bolts slack you can certainly move the tope edge back and forth considerably and this is vital if you are to avoid the quarterlights hiyying the screen pillar hard at the top. Yes you can adjust the quarterlight angle as well but I wouls keep all your options open until it starts coming together. If the quarterlight butts the screen too hard this is what initiates the crack of doom.
Iain MacKintosh

Good point, Iain. True, when reassembeling, keep all your options open and yes, beware of 'crack-o-doom!

Be careful though on this proceedure as one can be fooled a bit: with the center stay rod bolts slack, one can perceive adjustment possibilities. In the end though, the stay rod bolts need to be snugged, of course--and this is when the windscreen will find its final position. Thus my point of little to no adjustment. Perhaps its of bit of give and take between the screen and the quarterlights on the onset, yes. To do the final adjustment, imho, go with the quarterlight. Good luck with it. Paul
Paul Hanley

Now I'd say the opposite! Or to be more accurate do both bit by bit. Whilst there are adjustments on the 1/4-lights for sideways tilt I don't recall any for fore and aft tilt or position (other than non-standard shimming), whereas there is *definitely* adjustment of the screen to the body for fore and aft movement *and* tilt. I'd adjust the doors in the body first to get the correct shut lines, that will give the 1/4-light fore and aft position and tilt. Then adjust the screen to get the same tilt angle and the fore and aft position such that the rubbers are just touching the 1/4-lights all the way up, finally adjusting the bottom of the long 1/4-light leg to get the correct sideways engagement with the screen. There must be a clearance between these two or scuttle shake will cause the door skin to split i.e. Crack of Doom. Even with the stay-rod bracket tightened down there is still several degrees of tilt available in the screen frame as a whole, as the bracket is only lightly rivetted to the bottom of the frame. Before tightening the bracket bolts there is a considerable amount of fore and aft movement available of the frame as a whole.
Paul Hunt 2

Wow. I must have gotten very lucky to bolt in my windscreen and have everything fit! My adjustments were all made in the quarterlight and it fit great.
Jeff Schlemmer

Mark,

Both Mr. Hunt and Mr. MacKintosh are heavy hitters here and I bow to their years of experience although in some ways we're all in agreement--"do both bit by bit", as Mr. Hunt states.

As for quarterlight fore and aft tilt or position adjustment there is certainly position adjustment on the pull handle car doors. Granted, no tilt. The holes {for the long 7/16" nuts that hold the quaterlights to the doorskins} are rather large ovals, leaving about 3/8" or so adjustment options. There is also fore and aft adjusters at the bottom of the channels. I remember this clearly while reassembling my car after the body work was done. The quarterlights wouldn't fit as the body shop had gunked up the holes with excess bondo. Once I cleaned out the bondo, the ovals were completly exposed and fitting adjustment was easy. Don't know about the more common, later push button doors.
Paul Hanley

Mark, did you get someone to reassemble your windscreen or did you do it yourself. It's on my list of jobs to have the frames re-anodised then I need to get new glass and fit it to the frame.

I am feeling highly motivated right now after watching "An MG is born"!

Say, you're not close to Chch airport using airport transfers tonbridge are you? I am popping down that way in a few weeks to go to a friends 50th in Lyttleton.

Simon
Simon Jansen

Paul Hanley, no, no, not heavy hitters please, makes me feel some kind of a thug. Paul Hunt, that is correct but there is also quite a bit adjustment available on the quarter light, non standard you say but nevertheless it is there. These cars never fitted well and sometimes you have to file the slots in the top of the doors in order to get the quarter light back far enough because you must get the spacing correct at the bottom first. Now you can fit packers under the quarter light to door top fromt stud which is usually necessary to tilt the assembly back. Just use washers with the side cut out but then you will also have to pack between the quarter light mounts and the fromt of the door to ensure that this gap is not lost when the front two bolts are tightened and this is a real knuckle bruiser. Finally move the bottom of the guide sideways in the bottom bracket to get accurate side alignment with the windscreen pillar. And all this as you decide where and when you are going to finally tighten the first side of the windscreen.
Iain MacKintosh

Hi Guys,

Great advice so far. Keep it coming... the more advice I get, the easier the job will be.

Hiya Simon,
I didn't put together the windscreen myself. I know what a $%^# of a job it can be. I left it to the guys who did the bodywork on my B. They did a great job on it. It's now a complete unit (new glass, new seals, polished frame). I just need to drop it into the car and line up in conjunction with my door frames.
I would be interested to hear how you get on with your one.

I live on the other side of town from the airport. The airport is located on the west edge of Christchurch. Are you familiar with Christchurch at all? Are you down here for long?

Final windscreen question...
Any tips on easily getting the seal which butts to the car body flat when installing? Heard it done with a piece of cord, or just your finger (ouch?).


Mark
M C Duggan

Some folk tape the seal round and up to the front side of the glass but then you have to get all the bits out. I just use a piece of cord and my finger to pull it along as I seat the screen. People say this is a two man job but I think that three are necessary one at each end to keep the pressure and to hold one end firmly down as YOU enter the centre rod screws and fit the two bolts on one side. Gradually pull down the centre rod bolts whilst your mates pull down the other end and you fit the bolts. The bolts are difficult to fit but use a tepered centre punch to locate one threaded hole then fit the other bolt by hand and tighten it solid. Remove the punch and fit the second bolt. Then you can slacken the first and move the screen around.

Make absolutely sure that you can enter all bolts by hand. Clear the threads by screwing a well oiled bolt through from the back of the pillar before fitting. Preferably the holes should be Helicoiled.

Make absolutely sure that you fit the packers between the screen pillars and the body.
Iain MacKintosh

You have to fit the centre bolts before fully lowering the screen, and can only get them out when the screen has been partly lifted, because they are too long. This time I shortened mine while the screen was out. You need to put the points back on so as to centre the captive nuts so don't cut too much off in one go. But even then, unless you have cut way too much off, you can lift the nut from under the dash to engage with the bolt. It is new seals that cause the problems with installing the screen, when removing the screen for repainting but keeping the seals both removing and refitting were a one-man job. With new seals it was definitely a three man job to get it pushed down far enough to get the bolts engaged, plus a rubber-faced clamp. As Iain says it was also a three-man job to get the seal facing the right way - two to hold the ends down while one worked on the seal. Without that the tension in the seal just pushed the frame back up and the seal curled under again.
Paul Hunt 2

Paul, I liked the centre bolts to be fairly long and let them hang down as I lowered the screen. That way you could enter them early and at least get one fixing located. Appereciate your point too that if you get the screen well down on the seals you cannot then get long screws in and will have to cut them. Incidentally I replaced a cracked screen about three months ago into an assembly which had all new seals only three years ago. The bottom seal was just as bad and curled back to its original position needing three of us to refit.
Iain MacKintosh

Mark, only been to Chch once about 15 years ago! I was in school then. I will only be there a couple fo days. Fly in Saturday afternoon and leave again early Monday morning. One day though when i get the car done I am going to do a big road trip to the bottom of the South Island and back again. See a bit more of the country. I can pop in to see you/your car then!

Simon
Simon Jansen

Simon,

Christchurch has changed a lot in 15 years. Still a slower pace than Auckland. A great place to visit!

Look forward to catching up with you when your car is on the road and you do your big road trip.

My wife and I did a great trip around the south island about 12 years ago (back when my B was on the road). We still talk about it today. There are some great places to go to in the south island. Nelsons wine district through to busy Queenstown. Some awesome diverse scenery for driving in with the top down! Everything from the lush west coast through to Otagos dry plains.

Also, I have finished watching 'An MG is born'. Inspirational viewing! Funny... he went for the first colour scheme I was going for (silver with red interior). I changed my mind tho and went for Dark BRG and black interior.

Giviz a yell if you are ever down this way.

Mark
:-)
M C Duggan

Iain,

You mentioned fitting the packers as you install the windscreen. Quick question...

Should they have gaskets to minimise the risk of friction and/or rust starting? Or is this not an issue? I had just heard this mentioned before... that's all.

Thanks,
Mark
M C Duggan

"The bottom seal was just as bad and curled back to its original position needing three of us to refit"

Bum. I was hoping to remove and refit mine in the coming months singlehanded again after little more than a year since a new seal.

The outer seals *should* prevent any water running down the legs of the frame and onto the bolts. However as this cannot be guaranteed copper grease or similar on the threads seems a good idea (as in many areas) to reduce the incidence of corrosion causing future problems, I don't think friction is an issue.
Paul Hunt 2

I think there is a third item in this installation mix. The side window. You want the top of side window to be horizontal. Adjusting the mounting of the winding mechanism to the door is how one achieves this. To an extent this will influence the placing of the quarter light.

When I removed a windscreen to change the seals I found the seal mounted on the screen pillar was turned in under the pillar foot seal. Due to problems I had fitting the screen to the car on my previous B I cut the new seals shorter so they do not turn under the pillar foot seal. Is this a bad idea?
David Witham

I've cut my frame upright seals so the ends just brush the top of the chromed finishers on the door capping, which close just above the chromed caps on the ends of the seal that goes round the door aperture. At the time it seemed the only reasonable way without considerable distortion of the seal and pressure on the finisher.

To be honest, because the drop-glass doesn't have to line up with anything but the channels I think it is better to align the 1/4-light to the screen, the drop-glass to the front channel, and the rear channel to the drop-glas.
Paul Hunt 2

Absolutely right, the 1/4 light has to match up with the screen pillar and I,ve certainly never had a problem with the top of the glass being out of line. If it were a GT then you would have to take the B post into consdideration as well but the roadster is much easier here. I've cut my screen pillar vertical seal on the mitre so that it sits flush with the door seal alloy finisher but left it slightly proud at the top so thet the header rail holds it firmly in place and stops water getting in. My screen lower seal runs slightly under the pillar base seal and you can run a small bead of windscreen sealer in there just to be sure. Replace the pillar base seals as current rubber mouldings are crap and crack. They have a short life.

Paul, hope yours goes back together easier than mine did as I couldn't believe the seal would curl back to the original position after about three years.
Iain MaKintosh

This thread was discussed between 20/11/2005 and 22/11/2005

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