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MG MGB Technical - Replacing the Windscreen

Hi Guys

I am replacing my windscreen at the weekend on an mgb roadster 77 it is a complete assembly.

I was wondering if there are any expieriences people have had that would make it an easier job, i have got the worksheet off the MG V8 register which makes it sound resonably easy!!but i would imagine there are a few things i should take into account?

Thanks in advance for any information.

Graham

GLG Lavis

Graham

Check the archives. LOTS of good information there. You do need to be a member to access the archives. It is free and only takes a couple of minutes. Check both the B General and B Technical boards.

HTH

Larry
Larry Hallanger

Graham, how about posting the link to the worksheet so that we can all read what it is and then maybe offer additional tips, rather than us explaining it from ground zero.
Derek Nicholson

Ive done this and it was probably the most frustrating ordeal of my entire life. The bolts are difficult to access and very very difficult to line up when installing the new windscreen. Good luck

Ronald
RJS Stanis

Hey Graham,

I've done two so far. Went crazy on the first one until I worked out a couple of things:

1: Soak your seal in soapy water after it has been left out in the sun for a good time to warm up.

2. I found I could put the frame together by starting with the center rod, using this to bring the upper and lower together. Then installing the end frames. Next was to align the bolt holes. I used the grinder to make a set of pointed (rounded ends) on a set of bolts and used these as starters. Start the rear one first with the starter bolt, then I used a piece of 2x4 to raise the frame at the top braced on the rear lower part of the door frame (this was angled from the top of the windscreen frame to the bottom of the door frame)and pressed it down (very carefully on the windscreen frame) until the front hole lined up and installed the regular bolt. Then installed the rear bolt by pressing down on the frame.

After trying for a month, using this procedure I did it myself in one afternoon.

This is hard to explain, but I hope this helps.
James Huggins


The most important thing, and I can’t stress this enough, is the get the glass centered into the frame. Once this is achieved, it is not all that difficult, in fact last time it took about an hour to assemble the frame and wasn’t difficult. Unlike previous attemps, I took the time to get the glass dead centre. The more off centre the glass is the harder the job. I’d say 2 mm makes it impossible and 1mm very very difficult. The glass will not slide or move once it is in the rubber.
Mark the centre lines on the glass (vertically and horizontally) to a precision within half a mm (I’m not kidding here, the closer the better/easier the job). Mark the top and sides of the frame as well. Mark the rubber. Word of warning, the centre strut/rear view mirror support may not be exactly centre, don’t use it as a guide, a real trap.
You need to squeeze the side pillars together to compress the rubber a little. I did this by passing some cords around the windscreen and twisting a large screw driver in them to wind them tight. In order that I not fold the curved windscreen/frame in two, I placed a piece of wood in the centre outside of the windscreen and hooked the ropes around the outside of it, so they pulled toward the centre, rather than just pulling the side pillars toward one another.
Some people use large sliding clamps. If you have another person available, and the glass is dead centre, you might not need clamps rope etc.
I also used a little calking sealant, particularly around the corners. Don’t use too much, or you will need to undo the frame and scrape it off.
I use some detergent to help slip the rubber into the frame, which is quite deep.
The frame screws. These might be rusty so get some penetrating oil to put on them. I greased mine when I put them back.
Make a little drawing of which screw goes where, they are different lengths and you mustn’t get them in the wrong place.
If glass is a tiny bit out it is much much quicker to pull the frame apart completely and start over. You can get caught up in a “almost got the screw holes lined up ” trap and be “almost got it” for frustrating hours, as I did with the first one.

When you put the frame back onto the car do ensure that you have two spacers per side. There is the thick plastic one (approx 10mm) and the thinner (approx’ 4mm) spacer made of glove box material. I had to make up a replacement for the last. These spacers should be held in place by a centre screw and are under those small metal covers toward the top of the door jamb. I found it easier to take these covers off, and replace them after the frame was bolted in. I made lining up the bolts much easier. They are held in place by small rivets and clips. I used small self tappers instead of rivets when I replaced them.
If you don't have these four spacers then the windscreen will crack at the top corners with in a day or two. Personal experience here :(

Peter
Peter

Peter very good discription of how to install the glass in the windshield frame. However, Graham was asking only how to install the (complete assembly) frame to the car. Your last paragaph does however address this issue. In the future please read the question.
++..++

A sniper shooting from undercover, no less.
I am stung, however, some one might find it useful.


For those fitting already assembled windscreen FRAMES to their cars and using all new rubber.
You can also do the thing with a strong cord with screw driver (or strong stick) wound in it, to force the pillar down and line up the holes. Called a Spanish windlass I believe. You can generate alot of force, so do take care. If you pass the rope under the car (with a couple of towels to protect the paint) you can pull in the appropriate direction.
To get the the bottom seal lip going in the right direction, I used a couple of long bits of those thin flat blue plastic strips (they used to use metal)that they crimp around large carboard boxes. Passing from the dash side to the outside and kept dribbling detergent on them to keep them slippery
Anything thin, flat and strong and non abrasive would do, I just happened to have some of this blue stuff in the rubbish.
I pulled them out, before putting the bolts in.
Best of luck with it.
Unabashedly Peter

Thanks for all the info, Peter. These questions aren't asked in a vacuum, and the answers shouldn't be kept in one. The idea of these forums is to share information of use to all.

Phooey on the undercover snipers.

R.
Rick Stevens

Too bad we don't have the guys from the factory here to shed light on how it was don't in the old days. They must have had a system and tools for the job. It was probably one of the worst jobs on the line.
kids1

Thanks for the help,

It took 20 minutes to remove and 7 hours to fit!It needed changing due to crazing, might be the original screen so 30 years old.

I ended up removing the 2 covers inside the car that cover the spacers and shims, the method of using clamps on the corners of the windscreen frame and inside the car made it a lot easier (good protection required on the windsreen frame) but it still needed a friend to push forward on the screen to align the bolts.

Here is the V8 link for the worksheet http://www.v8register.net/subpages/V8NOTE349.htm

I got some new spacers from moss and they were metal and not plastic like the old ones? They also did not have the centre hole for the fixing screw, so i drilled these in position and fitted some self tapers. The old spacers (plastic) were broken in several places so the new ones were required.

I put some liquid on the area for the lower seal and started the seal by pushing from inside of the windscreen with the handle end of a spoon (not metal)you can run this along the underside of the seal and then pushing down on the windscreen made the seal go into the right position.

I then made sure the windscreen was in the correct position for the doors (closed the doors to check) and fitted the roof and tightened up the bolts.

The centre bar lower attachment bolts are a bit long, so i shortened them so they did not fowl the windsreen internal rubber during the fit.

It seems to have worked, i guess only time will tell.

At least i can now see through the windscreen now when going into the sun.

Graham
GLG Lavis

P.S

It is up there with the worst jobs to do on an MGB

Graham
GLG Lavis

Graham,
Make sure you’ve got those additional spacers, two spacers per side, the thick one and the thin one.
If you haven't whip out to the garage and loosen off the bolts. With my first windscreen both the thinner shims had been left off (along with one of the thicker spacers) by some former owner or glass shop person (destined for some biblical style punishment I hope) and the bolts left loose. When I replaced the windscreen I tightened up the bolts with just the new thick set in place. All looked well and there was some considerable self congratulation. We drank up a bottle of red infact. About two days later a crack appeared at the top left hand corner, on the outside of the laminate. A second crack appeared on the top right hand corner a week later. I can't tell you how I felt about that! There was a weeping, wailing and gnashing of teeth, to continue the biblical analogy.
You don't always need them (spacers) I'm told, it depends on the car. You can tell if you don't because when fitting the frame it should slide tightly over those spacers, so you may tighten up the bolts without flexing in the bottom of the screen. If its a bit loose , you need some more spacers/shims. Any water proof material will do.
Obvious in retospect, but these things always are.
Peter

ps you don't need to take the bolts right out, just loosen them off and then push something in between the two bolts. A bit of sheet metal, bit of a tin can whatever you've got that you can push in there. Then tighten up again. It's all hidden under those covers so it doesn't have to be pretty.
peter

Unabashedly Peter - Thanks for submitting such a comprehensive explanation. Sharing personal experience such as yours is much more helpful than trying to sort out Haynes & the rest of the manuals. They never seem to have any problems or offer best steps to make the job happier. For some reason, they never seem to get covered in grease or blood either.

I have the windshield replacement experience coming up and very much appreciate your insights as they will help make the challenge that much easier.

Thankful Joe

Joe Lucas Manitoba

Peter,nice discription.Maybe someday ++..++,The World(above response)can contribute something more valuable to this website than pointing out who didnt read what!
Rich Osterhout

Thanks Peter

When i fitted it there was a bit of resistance with just the thick spacers but this could have been it not going in straight, i will have a look soonest, and put some shims in, but as you say i do not have to take the bolts out fully again.

The old frame had no shims on one side and a full shim on the other.

Lets hope it is not to late..........

Graham
GLG Lavis

Yes Joe, I've noticed that the Haynes photos show guys in spotlessly clean crisply starched and ironed overalls, full of vim and vigor, with their neatly mannicured fingernails. Hardly human in fact. I suspect that these persons are actors/models, and to do the actual job, they use STUNT mechanics, fearlessly begrimed/bloodied persons, with slipped disks, gashed knuckles and mashed fingers. Extraordinarily long thin powerful double jointed fingers, by the way, able to reach places that mere human beings such as myself are not even able to see, let alone get a spanner into..I am also sure that they have at least two sets of elbows on their freakish long arms. Tolkein must have used these people for inspiration. Same period see, it must be true. (yes I've opened another bottle of Red).
Generally by the time I get to the end of a Weekend of groveling around under the car, dash etc; I am neither spotlessly clean nor smiling or energetic. Feeling distinctly subhuman actually. I’m not sure why I do it, something to do with “never surrender” I guess. "the few the proud etc.."
The word I particularly fear in Haynes manuals is “DRIFT”, as in ”Drift the component clear” Ask Jesus Christ to attempt this, because no one else will have a chance that’s for sure. It usually means that the parts are almost certainly completely corroded together and anyway were originally pressed together with a 10,000 ton press built by Isaac Brunel.

Does anyone else have a ‘favorite’ heart stopping phrase that they’ve run across in the Haynes manual?
‘Special tool XYZ’ generally causes my heart to sink.

peter

hahah

peter, i like your style!

i have found this thread very helpfull as im about to embark on the 'windscreen mission' in a few weeks. i removed my screen in the total stripdown of my car a few years ago and it has remained in an assembled state in my roof ever since. i am about to tear it down, polish, reseal and reassemble in due course.

although i am a bit peeved.... i think i have mistakenly used the spacers you talk about to space my front guards when attaching them and as i have just sealed them in and had my final paint applied, theres no way im going digging for them!!

are these an oval spacer with a slot for a hole?

as for the sniper, they are around... im sure they just to try and wind you fellas up!
Innes Bint

Took the door cover plates off today and losened off the bolts and there was not any space to put in some shims, so hopefully the screen will not crack.

Heres hopeing.

Graham
GLG Lavis

ahhh, i did have the correct guard washers after all! in hindsight, im sure my car never had shimms- only the bracket.
Innes Bint

This thread was discussed between 14/03/2007 and 23/03/2007

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