C3 Water Leaks
Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 1,009
Likes: 62
From: Houston Tx
C3 Water Leaks
Hi all. I drove 76 C3 for the 1st time during major rainy weather yesterday. Water is getting into the car somehow. It's getting in and dripping just above the hood release on the driver side. The kick panel trim was wet, as well. Does anyone know what could be the cause before I start pulling stuff apart? It's leaking the same on the passenger side, as well but not as much. Is there a vent or seal or something behind those kick panels? Thanks.
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Yes there are vents and let's hope it is not from a rusted birdcage by the window bottom. Take a hose and slowly run water into one side and then the other and get a light and try to see where the leak is coming from. Remember water leaks can fools you as it travels to the lowest point.
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
Could be several things. Weatherstripping issues hopefully or bird cage rust on the other extreme. Pull off the kick panel and check the body cavity where the frame mount lives. If there is a bunch of rust and lots of flaking then you probably have bird cage issues. Been there, done that, no fun.
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
The bird cage is actually the metal framework that surrounds the passenger compartment that all the fiberglass is bonded to, including the windshield frame which is where the problem usually occurs. If the metal rusts through, especialy somewhere around the windshield, water will travel down to the sides and show up in the kick panel area either inside (drips under the dashboard) or in the cavity behind the panel where the body mount lives. Either way gives you soggy carpet. It can be patched or the whole frame replaced. It's just not cheap either way.
Check your weatherstripping and window fitment very carefully first before you panic.
Check your weatherstripping and window fitment very carefully first before you panic.
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
Sealant was used to seal between the firewall and the wiper bay, over the years it dries out. There was also sealant around the wiper transmission mounts, it gets old and leaks there also. You need to get down there and watch while someone runs a hose, and watch and see.
Do a search for sealing wiper bay.
Do a search for sealing wiper bay.
Burning Brakes
Joined: Feb 2008
Posts: 1,042
Likes: 19
From: Oswego New York
I'm not particularly familiar with your '76 (I have a '70).
When I had water in my floor pans, I removed the kick panels, then the air vent assemblies, to access the body cavity. It was plugged with debris, preventing the water from draining out. It took a while but I repeatedly vacuumed/flushed to clean out the cavity, and that resolved the problem. Hope this helps.
When I had water in my floor pans, I removed the kick panels, then the air vent assemblies, to access the body cavity. It was plugged with debris, preventing the water from draining out. It took a while but I repeatedly vacuumed/flushed to clean out the cavity, and that resolved the problem. Hope this helps.
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Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 1,009
Likes: 62
From: Houston Tx
C3 Water Leaks
Hi all, I am resurrecting an old thread. I finally got around to figuring out how the water is leaking in from under both sides of the dash in my 76.
It's leaking between where the firewall and wiper bay meet. All the sealant originally used by GM is all cracked up. My question is what is the best stuff to use to seal this back up both in the interior and exterior? Thanks.
It's leaking between where the firewall and wiper bay meet. All the sealant originally used by GM is all cracked up. My question is what is the best stuff to use to seal this back up both in the interior and exterior? Thanks.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Team Owner
Joined: Sep 2006
Posts: 31,274
Likes: 4,366
From: Westminster Maryland
Hi hg,
You can use 3M Strip Sealer or 3M Seam Sealer.
It helps if you have clean surfaces to apply it to.
The seam doesn't need to be 'pretty', but it should be completely free of 'debris' so the sealer can bond to the fiberglass.
Regards,
Alan
I'm thinking you're asking about this seam between the cowl and firewall?
You can use 3M Strip Sealer or 3M Seam Sealer.
It helps if you have clean surfaces to apply it to.
The seam doesn't need to be 'pretty', but it should be completely free of 'debris' so the sealer can bond to the fiberglass.
Regards,
Alan
I'm thinking you're asking about this seam between the cowl and firewall?
Last edited by Alan 71; Dec 1, 2017 at 02:21 PM.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
Hi all, I am resurrecting an old thread. I finally got around to figuring out how the water is leaking in from under both sides of the dash in my 76.
It's leaking between where the firewall and wiper bay meet. All the sealant originally used by GM is all cracked up. My question is what is the best stuff to use to seal this back up both in the interior and exterior? Thanks.
It's leaking between where the firewall and wiper bay meet. All the sealant originally used by GM is all cracked up. My question is what is the best stuff to use to seal this back up both in the interior and exterior? Thanks.
I used flex seal, 3 coats, and it sealed up great.
Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 1,009
Likes: 62
From: Houston Tx
Hi hg,
You can use 3 M Strip Sealer or 3M Seam Sealer.
It helps if you have clean surfaces to apply it to.
The seam doesn't need to be 'pretty', but it should be completely free of 'debris' so the sealer can bond to the fiberglass.
Regards,
Alan
I'm thinking you're asking about this seam between the cowl and firewall?
You can use 3 M Strip Sealer or 3M Seam Sealer.
It helps if you have clean surfaces to apply it to.
The seam doesn't need to be 'pretty', but it should be completely free of 'debris' so the sealer can bond to the fiberglass.
Regards,
Alan
I'm thinking you're asking about this seam between the cowl and firewall?
By the way Alan, your car picture looks great
Thanks.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
No matter what you do, run water everywhere before re installing the dash. It will leak in more than one place.