Tech Stuff

MGB Windshield Replacement

Replacing the windshield on an MGB roadster can be completed with a few simple tools and a reasonable amount of patience. Removing the windshield assembly is a simple task. Loosen the two bolts securing the bottom center rod bracket to the dash top. Leave the center rod assembly intact to hold the windshield assembly together. Remove the four bolts securing the windshield pillars to the body. Completely remove the center rod bolts. Withdraw the entire windshield assembly from the car.

	MGB Windshield Replace Clamp

Begin dismantling the windshield by removing the rear-view mirror and visors. Remove the nuts and washers securing the center rod to its top bracket, and withdraw the rod through the bottom bracket. Unscrew only the outer three screws securing the top rail to each pillar. The long outer screw on each side is a Moss #408-057, the two short inner screws on each side are Moss #408-056.

Peel back the frame to body seal (Moss #282-410) just enough to remove the two screws on either end of the bottom rail. With a soft mallet, gently tap the pillars free of the glass and rails. The top and bottom rails can now be removed. Peel the glazing rubber away from the glass.

Inspect and clean the top and bottom rails. Check the corner brackets on the pillars. Mark the center of the new windshield glass with a crayon so it will be more easily lined up with top and bottom rails.

Place the new glazing rubber (Moss #282-420) around the windshield glass. Inject a bead of windshield sealant into the groove in which the glass sits. Lubricate the outside edge of the glazing strip and the inside of the top and bottom rails with a soapy water solution. Push the top and bottom rails into place slowly

Fit the side pillars into place. (If the top and bottom rails are not pulled together enough, then temporarily assemble the center rod or use a carpenter’s wood clamp to gently ease the rails closer.) If the side pillars balk, try tapping with a soft mallet. Again, be sure to go slowly.

Once all frame members are in alignment, replace the screws in the proper holes. On the top rails, the short screws belong on the two inside holes on either side of the rail and the long screws go in the outermost holes on each side. Attempting to use the wrong screws may easily result in breaking the glass.

With the windshield firmly assembled, scrape off the excess sealant and refit the center rod. Refit the frame to body seal. If replacing this seal (Moss #282-410) is necessary, now is the time to do it. Lubricate the bottom channel with a soapy water mixture and slide the leading edge of the seal into the channel while easing the seal along carefully where it enters the channel. This is a very slow process. Replace old windshield pillar grommets: L/H, Moss #282-450; R/H, Moss #282-460.

Apply a bead of sealant to the top of the grommets before sliding them into place on the pillars. Apply another bead of sealant to the bottom of each grommet and along the flap of the frame to body seal. Ease the windshield assembly back onto the body.

The windshield should not be forced into place; it is better to let it sit overnight to compress the new rubber seals. Tighten the pillar bolts one at a time while checking and adjusting the fit to the door vent windows. Once in place, recheck the fit to the vent windows and top. Check the seals between the pillar and vent windows and top. Replace if necessary with two of Moss #282-400.

Finally, refit the mirror and visors. If done patiently and carefully, the roadster windshield should now be draft and leak-proof. A good source of information about MGB restoration is Lindsay Porter’s MGB Guide to Purchase and D.I.Y. Restoration, Moss #211-365.


Editors Note: Article reprint from Moss Motors Technical Tips
https://www.mgexp.com/article/moss-motors-mgb-tech-tips.225