MGExp

MGB & GT Forum

MGB Leaking windshield rubber

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

MGB Leaking windshield rubber
#1
  This topic is about my 1977 MG MGB
KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
Hello all. Yesterday I was caught in the rain with my 77 B and it was the first time I drove it in the rain. I knew the car leaked a little but yesterday's heavy rain was running through the lower rubber of the windshield and down onto our legs. I couldn't believe how much water was leaking into the car.

I noticed that the rubber surrounding the windshield isn't installed correctly and there are huge gaps at the outside and inside bottom.

Can I get the rubber changed without taking the windshield frame off or does the whole assemble have to be removed?

Thanks for the help.

Kevin

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
You have to remove the assembly to put the cowl to w/s seal on.
Edit: This is probably my least favorite job of all. Some of the new seals are so hard that you can't use the method that Twist shows in his you.tube video. To pull it into place takes 4 big guys and lots of lube.



Edited 1 time(s). Last edit at 2017-10-09 10:37 AM by chris.


Member Services:
Used English car parts.
KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
That's what I've heard Chris. I thought maybe a glass company could pull the rubber out and reinstall the glass as they do with modern cars.

My Mickey Mouse repair manual says throw some silicone around the bottom but I'd like to avoid that.

sws615 Avatar
sws615 Stephen Struck
Grand Haven, MI, USA   USA
1967 MG MGB GT
1975 MG MGB "Commission # G23N124120"
2015 Acura MDX
X2. Not a fun job. While you're considering how and when to do that, a tube of silicon caulk is your friend. Sounds like you have big gaps, but it's also helpful to put a narrow bead of silicon under the front of the rubber gasket. Use a plastic tool of some sort to pry it up, and then run it across, applying the silicon right behind the tool.

Then there are the common leaks around the top hold down clips......

Steve

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
Steve,

Are you referring to the larger rubber gasket that runs along the paint outside the car? That sounds like a good idea. I was avoiding the silicone because it seemed so easy but could be dumb if something went wrong.

I'm never in the rain with the car but if I get caught again I'd like to have a fighting chance.

Thanks for the advice.

sws615 Avatar
sws615 Stephen Struck
Grand Haven, MI, USA   USA
1967 MG MGB GT
1975 MG MGB "Commission # G23N124120"
2015 Acura MDX
Kevin,

Yes, that's what I was referring to. If you get bleed out after the gasket goes back into place, it's easy enough to wipe off the excess. Kind of a band aid approach, but it will keep you dry(er) until you can redo the whole windshield.

Steve

KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
Thanks. Sounds like a great idea.

Wachtmans Avatar
Wachtmans Wouter Strodijk
OVERVEEN, Noord Holland, Netherlands   NLD
1974 MG MGB "The Bee"
1974 MG MGB "The Bee"
1974 MG MGB MkIII "The Bee"
I used Sikaflex primer (black), which penetrates into the old porous rubber. Bonds with humidity and stays flexible.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
Thanks. That will blend in better than a clear silicone.

I'll check it out.

jjh1118 Avatar
jjh1118 Jim Hargrave
Bogota, NJ, USA   USA
1975 MG MGB "The Little Car"
Before tackling the windshield seal, check Tom's Knob to see if they are full of crud. Mine were and once I cleaned them out no more wet feet!

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
half there Dan Hooper
Wimberley, Texas, USA   USA
I just replaced that seal in my 76B. After getting frustrated with the progress of installing the seal in the channel, I pulled it back out and used wire pulling lubricant. (Used for pulling electrical wire through conduit). Was able to install the seal in about half an hour by myself. And it will not degrade the rubber seal.

Dan

KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
Thanks Jim.

KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
So, the front seal under the windshield and running along the cowl outside can be changed with removing the windshield frame?

Brian E Avatar
Stanwood, Washington, USA   USA
In my experience, you'll need to remove the frame to change out the lower rubber seal. I've found that using a small amount of silicone inside the corners of the windshield frame, just enough to make a waterproof joint at the top and bottom where the frame parts overlap, and a small amount under the front seal where there are ridges in the car body was enough to ensure that it stayed dry inside inside.

It is possible to lift the front edge of the lower rubber that goes between the windshield frame and the car body in order to get some silicone under there - that can possibly help. The points most prone to leaking are at the raised ridges at each side of the body and where the bottom rubber seal transitions into the mall rubber boots under the end posts. Wind will tend to push water into these areas and under the rubber at those points if the rubber seal isn't completely seated.

Taking the windshield frame off is a bit of a pain, and even more so getting it back on. In theory, it is only 4 bolts, but there is not a lot of room to work. A warm shop will help when it comes time to compress the rubber when putting the frame back in place, a second set of hands will be a lot of help holding the windshield down and aligning it while it is bolted back in, and some lube makes getting the seal that surrounds the glass back in place possible if you're dealing with that too.......

KPK Avatar
KPK Silver Member Kevin K
Cumberland, Rhode Island, USA   USA
1977 MG MGB "Emma"
Thanks Brian. During the rainstorm I did have a magnetic cover over the vent in front of the windshield, so I know it wasn't coming in there. I'll have to do some garden hose research and see where the gaps are.

Your information is very helpful. Thanks so much.

Kevin

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions

Members Sign In   or   Create an Account

Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster