MGB Windscreen Replacement
June 23, 2012 - Plano, Illinois

After a long fight with one bolt, we discovered an easy access, just remove the brake test switch.

Click for BIGGER pictures, average 52K

Such a wonderful place to be on a warm summer day, a nice little horse ranch in the country near Plano, Illinois. If you include the residents, we had four club members, with three MGs. Don Haag owns the yellow MGB in need of new windscreen. Barney Gaylord drove the MGA. Victor L'Heureux came a log way in the red MGB. Thomas E Lancaster Sr with the black truck was there for a few hours before he had to leave, but we recruited a couple extra hands later in the day. After inspecting a few of the local collector cars we got to work about 10:30am.

Removing the windscreen wasn't too bad a job. Fifteen minutes for the first three bolts, and 45 minutes for the fourth one tucked in behind the dash high on the right. Note to self: Need a 1/4" drive 9/16" socket with universal joint and 6" extension. It also helps to remove the glove box liner box to have access through that dash opening for working the two bolts on the right side. Two more bolts from bottom of the center stay, and it's lift off time.

Disassembly of the frame was a snap. The center stay rod has an extended nut at bottom that looks like a big spoke nipple from a wire wheel. The top rail had ten screws exposed on the top surface only. That left a narrow tapping plate loose inside that we would learn to deal with later for reassembly. And there was that pesky plastic retainer for the sun visor that was part of the reason for the broken glass in the first place. Someone had been here before, as the screws all came out easily, some of the screws were incorrect length, at least one was not screwed in just sitting there.

Pull the rubber post grommets off the bottom, then pull the rubber seals out of the side T-slots. There were multiple tell-tale marks in the bottom rubber seal. But it was a long time ago, because all of the rubber parts were in seriously decomposed condition. The bottom seal is hiding two screws at each end, and once those are removed the end brackets can be pulled out.

We drew a diagram of the assembly on a sheet of paper and taped all of the screws down in respective order to remember what length screws go in which holes. That's when we discovered a couple of them were the wrong length.

Easy to pull the bottom rail off and leave the old packing rubber on the old glass. The bottom seal comes out of the "T" slot with a little tug, which of course is a whole lot easier then sliding a new one back in. Chuck the old broken glass outdoors to get it out of the way.

After spending a little time cleaning and polishing the aluminum frame, it was easy to remove a few rivets by carefully grinding the head off and then punching out the loose tail.

It had been suggested on a few occasions that a rubber friendly lubricant might be K-Y Jelly. Okay, but you have to be able to explain to your wife why you keep that stuff in your tool kit. It was previously just a joke, but we thought we might give it a try to settle the matter one way or the other. At first it looked like a really good idea, nice and slippery, easy to apply, and the bottom rubber seal started to slip in easily. After a minute or so of moderate progress part of the T-rail on the rubber seal jumped out of the T-slot, and we had to pull it back several inches and start again. We found that long nose pliers with bent tips make a very good pulling tool, and a wood block clamped to the table edge makes a good end stop for the bottom rail. After a couple of false starts and a little more fussing we figured out how to keep the rubber "T-edge engaged in the slot, then agreed on who would push, who would pull, and who would be shoving the center along with both hands.

By that time the lubricant began to dry out and was getting more viscus and sticky, slowing progress considerably. When we had the seal about half way across the bottom rail it was tough going, so Don called his son Donny for additional hands. We were then spritzing soapy water on the parts to keep the rubber seal damp and slippery. With four pairs of hands the progress was much better, and in a few more minutes we had the seal all in place. No pictures of this, because all hands were busy pulling or pushing, and there was no one left to hold the camera. We knew in advance that installing the bottom rubber seal was a tough chore. After this experience we might work out better methods of pulling the thing into place, when the situation comes up again.

Placing the new rubber glazing on the new glass edge was delightfully easy. With a touch off soapy water the frame rails would slip on easily as well. Then we use some web strap clamps to pull it all tightly together while we installed lots of little screws. It sounds easy, in theory, but in the real world it is a bit more of a battle. Actually it's more like a Chinese puzzle, figuring the best sequence of assembly and trying to get flat tipped screws into sharp edge threaded holes. A little alignment punch here, a little prying there, touching off the first thread of a screw tip with the grinder, and three pairs of hands holding things in alignment to get a screw started. It would have been better if the bottom rail hadn't popped off of the glass while were were working on the top rail, but that was one of the more minor problems. We stopped for lunch about that time to re-group and think about the next plan of attack.

In the end you just have to decide that failure is not an option, and have confidence the you are going to succeed, eventually. After something is finished it seems like it was somewhat easier than reality. After the windscreen was assembled we took another short lunch break before installing it on the car. Good that we did, because it would be more hours working before the job was done. Don took another quick trip to the hardware store to buy a couple 1/4-inch bolts a bit longer to get started on clamping down the center stay rod base plate.

Again in theory it looks easy enough, only six bolts to install, two on each side and two in the center. Then again, sometimes all the optimism in the world only amounts to wishful thinking, and the job is only accomplished through sheer grunt and determination. Place a length of clothes line cord inside of the curl on the bottom seal lip. Drop the windscreen into place, and have two brawny guys hold it down while a third will pull the cord to pull the rubber seal lip forward onto the top of the car body. That was one of the few things all day that actually went exactly as planned and was done in a minute. That leaves two guys holding the assembly down to keep the seal from curling under again, while a third is trying to install some carpenter clamps on the frame feet. After a couple of false start here, and pulling the cord a couple more times, we did finally get through that phase.

Once the post base clamps were in place we applied a longer bar clamp from top of windscreen to the horizontal steel tube below the dash. Grab a light and mirror to see the bolt holes on the side behind the dash. Get one or two guys to push and pull fore and aft on the top corner while you line up the bolt hole underneath, doing a few adjustments on the long bar clamp. The trick here is to use the clamps to apply the force, and the hands to apply the finesse. It was also a big help to grind a point on the bolts (like traditional body bolts) to get the thread started when hole alignment may not be perfect. Get the more accessible bottom bolt in first, and the top one with lesser access will be much easier. After a half hour of more fighting with the upper bolt on the left bank, it was suddenly discovered that removing the brake warning and test light left a nice hole in the dash in exactly in the right place for socket wrench access to the top bolt. Duh? Why didn't someone discover that several hours earlier?

By that time we finally had the system down pat, and the rest of the job went better. Some of the bolts were in locations where the only wrench access was one flat at a time with an open end wrench. This was slow going, but steady progress finally gets you there. The last move was to close the car doors and align the side of the windscreen with rubber seal to mate squarely against the vent window frame, and tighten the post bolts last. With all bolts tight the new bottom seal was lying flat out on the body cowling as it should, all bright and shiny, sweet as could be. Don spent a little time with the Windex to clean it up and admire the end result, and of course we had to get the victory picture. At 10:30 pm we called it quits and left installation of the glove box for Don to do later.

On 11/10/2014, Charles Maroon in Nevada City, CA wrote:
"Accessing the upper left frame bolt through the brake pressure hole is an EXCELLENT and appreciated suggestion. In return I offer this tip; when installing rubber gaskets into metal channels - coat both surfaces with Johnson's baby powder to reduce friction, this works for me without fail. I also place the new gasket in the sun for a few hours to warm and relax the rubber".