The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-23-2018, 07:40 PM   #1
zac
Registered User
 
zac's Avatar
 
Join Date: Jul 2008
Location: louisville, ky
Posts: 500
Has the Windshield/Cowl Leak Issue Ever Been Solved?

I assume most people know what I’m talking about. I’ve tried most things people have suggested here, even some of the crazy stuff. My ‘72 burb had the problem, my ‘70 does too....
zac is offline   Reply With Quote
Old 04-23-2018, 10:12 PM   #2
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,270
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by zac View Post
I assume most people know what I’m talking about. I’ve tried most things people have suggested here, even some of the crazy stuff. My ‘72 burb had the problem, my ‘70 does too....

It has been solved by many people. There are a couple of different scenarios so what exactly are your symptoms?

LockDoc
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 04-23-2018, 10:25 PM   #3
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,753
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

If the are no holes rusted through the cowl area (common problem) and the seal is a good quality pliable rubber unit. Then most likely it is poor fitment of the panels when the cab was built. My Burban was pretty clearly built on a Monday or Friday as the fit up on the roof and window frame is terrible. (The circled gap in the 2nd photo is 1/8") I'd bet it had problems from day one. I put about ten hours into making sure the seal had a nice flat surface to press against hoping to keep the water out. Not that here in Oregon it would be an issue but just in case I travel somewhere wet.

Man I tell you, LockDoc has the fast fingers on the forum as well as instant recall.
Attached Images
   
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 04-24-2018, 12:09 AM   #4
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,270
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

-
Here is where my '67 Panel Truck was rusted. You couldn't see it from the outside but you could see it from the inside with a good light.


Also where HO455 shows at the top, and the drip rail above it, which would cause the water to run down through the "A" pillar.

HO455: I guess that is because I spend WAY too much time on here....

LockDoc
Attached Images
   
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 04-24-2018, 12:27 AM   #5
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,753
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

My theory is water gets in at the top and is trapped at the bottom in the gaps inside the seal and eventually rots its way through. This in some part based on the factory manual saying that the upper corners of the glass may have to have sealant injected under the seal if leaks occur. I bet the dealerships just loved dealing with that. I would bet that none these trucks left the factory with sealant in the corners. Well maybe in the later years if the dealers rebelled.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 04-24-2018, 02:39 AM   #6
Hutch
Registered User
 
Hutch's Avatar
 
Join Date: Oct 2001
Location: Grapevine, Tx.
Posts: 2,140
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

zac
I don’t think it was ever completely solved
Here is an old link to some insight from way back in the day
http://67-72chevytrucks.com/vboard/s...ad.php?t=74670
__________________
John Hutchison
Grapevine,Texas

68 1/2 t swb
68 Mustang
69 Jaguar
71 1/2 t swb
88 Supra CompTs6m
93 Escort GT
2005 Corolla XRS
Hutch is offline   Reply With Quote
Old 04-24-2018, 08:25 AM   #7
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,270
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by Hutch View Post
zac
I don’t think it was ever completely solved
Here is an old link to some insight from way back in the day
http://67-72chevytrucks.com/vboard/s...ad.php?t=74670

I stand by my statement that it has been solved by many people. All that thread proves is that the problem has been around for a long time. A couple of things you have to remember is that everyone's situation will be a little different, and that 90% of the people that cure the problem never report back and post exactly what cured the problem for them. I cured mine on a couple of different trucks by using sealant from the top corner of the gasket over 6" and from the top corners down 3" and I have posted that statement many times.

LockDoc
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 04-24-2018, 10:12 AM   #8
zac
Registered User
 
zac's Avatar
 
Join Date: Jul 2008
Location: louisville, ky
Posts: 500
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Ok guys, good stuff. I have been awake all night at work and probably can’t generate a coherent response right now. But here goes. My ‘72 was a rust bucket, so that very likely was the culprit. Even after going over everything literally with a tube of caulk more than once, it still leaked like a sieve. I was sure I tried LockDoc’s idea, but now I actually think I sealed the bottom of the seal, which likely aggravated the problem. My ‘70 is actually pretty decent. Cowl area been disassembled more than once. Tried various things, but never saw any issues there. Has a new windshield and seal installed by PO, but I’ve had the truck 8 years. I have never thought of the body fitment angle. I will investigate that. What “sealer” are we talking about in the upper corners of the windshield seal? Just to be clear, this is the water running down the inside next to the cowl vents, both sides. Little puddles in the corners of the front floorboard. Starts raining, it leaks. Rain stops, leak stops.
zac is offline   Reply With Quote
Old 04-24-2018, 08:01 PM   #9
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,270
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by zac View Post
Ok guys, good stuff. I have been awake all night at work and probably can’t generate a coherent response right now. But here goes. My ‘72 was a rust bucket, so that very likely was the culprit. Even after going over everything literally with a tube of caulk more than once, it still leaked like a sieve. I was sure I tried LockDoc’s idea, but now I actually think I sealed the bottom of the seal, which likely aggravated the problem. My ‘70 is actually pretty decent. Cowl area been disassembled more than once. Tried various things, but never saw any issues there. Has a new windshield and seal installed by PO, but I’ve had the truck 8 years. I have never thought of the body fitment angle. I will investigate that. What “sealer” are we talking about in the upper corners of the windshield seal? Just to be clear, this is the water running down the inside next to the cowl vents, both sides. Little puddles in the corners of the front floorboard. Starts raining, it leaks. Rain stops, leak stops.

I just used Black RTV sealant on mine. That leak would most likely be top of gasket or drip rail corners.....

LockDoc


LockDoc
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 04-24-2018, 09:03 PM   #10
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,753
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

I would get a friend and a hose then dive under the dash with a good light. I would bet there are holes in the cowl that are the culprits. So have the friend slowly move the hose around the cowl vent area while you watch for water. It can come in from the top or the side. The driver side is easier view unless you pull the jockey box. The link below has good cut away photos showing the common problem areas.
Good luck. Been through this myself.

http://67-72chevytrucks.com/vboard/s...d.php?t=721974
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 04-24-2018, 09:22 PM   #11
Southpaw69
Registered User
 
Join Date: Jan 2018
Location: Modesto, CA
Posts: 92
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

These are all different on how far along the rust damage is. It doesn't take much of a rust hole letting water in to rot out the floors
On mine there was leaves and dirt packed inside the cowl where it curves down. This caused rust right on that seam. I removed the glove box(oddly, they had a new one in there when I bought it lol) and found a small hole up next to where the antenna hole is. I used a wire wheel then steel epoxy putty on it. Dabbed some silicone on the antenna hole and finally sprayed the inside of the cowl area with rust encapsulator. It's water tight at this point, hopefully it lasts.

the toughest part is finding exactly where the water is getting in, once you do, you can fix the source. Now to patch the kick panel and inner and outer rocker...
Southpaw69 is offline   Reply With Quote
Old 04-24-2018, 09:56 PM   #12
davischevy
Senior Member

 
davischevy's Avatar
 
Join Date: Sep 2008
Location: Harrison, Arkansas
Posts: 9,780
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

I have never had one leak twice. As Locdoc said, RTV 6" to 10" in from the corner at the top and a few inches down the side and it will more than likely be sealed.

IIRC, the assembly manual shows the sealant at the top corners.
__________________
other Larry


Build thread, Arkansas K10
https://67-72chevytrucks.com/vboard/...=755797&page=5





The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.
davischevy is offline   Reply With Quote
Old 04-24-2018, 10:26 PM   #13
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,753
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

So to answer the original question. Only on a case by case basis. Although I hear there are still some folks pushing for the GM recall settlement.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 04-25-2018, 09:48 AM   #14
StingRay
Senior Member
 
StingRay's Avatar
 
Join Date: Mar 2000
Location: Saskatoon,SK,Canada
Posts: 2,476
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Silicone is the worst possible choice to seal around a window. It's actually not waterproof. It will absorb moisture and let it through trapping it behind the silicone. This will accelerate corrosion. There are two kinds of silicone, acetoxy and methyloxy based. Acetoxy based smells like vinegar or acetic acid. It will start a corrosion process. Methyloxy is less of a problem. If you are going to seal the area with a permanent sealant use urethane and clean an prep to the tech instructions. Butyl is best as a removable product and is recommended in the factory assembly manual around the window opening when the windshield is installed. It used to be very common for glass shops to pump butyl into the void of the windshield gasket after the windshield was in.
__________________
Saskatoon, Saskatchewan
Canada
StingRay is offline   Reply With Quote
Old 04-25-2018, 01:02 PM   #15
zac
Registered User
 
zac's Avatar
 
Join Date: Jul 2008
Location: louisville, ky
Posts: 500
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Ok, I've had some sleep and a couple minutes of free time, and I see some problem areas, both above the upper windshield corners. Something tells me the design of the rain gutters maybe directs water into these areas in certain situations. The area with the pinhole is the driver's side and it has the worse leak. Apparently all the focus I put on the cowl area somehow made me miss this, although I'm sure I looked at this area and I don't remember it looking like this. The truck has been sitting indoors more or less abandoned for the last 3 years since I even thought about this. But sitting indoors in Kentucky for 3 years is like sitting outdoors for 30 in Colorado from a corrosion standpoint. I'm looking for a reasonable short term plan here to get me through to the part where the windshield comes out and repairs are made. I promise to report back what happens.
Attached Images
   
zac is offline   Reply With Quote
Old 04-25-2018, 02:26 PM   #16
Bowler1
Registered User
 
Join Date: Apr 2017
Location: Brownwood, Texas
Posts: 55
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Hey guys all of you are on right track as a former autoglass installer I have seen leaks on every make and model car and truck. GM had some of the worst leaders of all. 67 to 72 being the worst as I mentioned the firewall was one, down through the cowl the heater opening, the lower windshield corners which was usually caused by no sealant at top corners. Remember when checking for water leaks always start at lowest point and work up.
Bowler1 is offline   Reply With Quote
Old 05-18-2018, 09:21 PM   #17
zac
Registered User
 
zac's Avatar
 
Join Date: Jul 2008
Location: louisville, ky
Posts: 500
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Update: I sealed the upper corners of the windshield. My truck has that stainless trim, I'm glad I did a search on this board before I tried to pry it out. I pulled the cowl vent piece off and realized I obviously had an issue with the antenna lead. So I sealed that up. I also found a gap in the cowl area, more on the passenger side than the driver's, so I sealed both of those also. Then I left the truck outside to get rained on while I did the rockers and cab corners on my '79. Of course it didn't rain until the last couple days.

The passenger side has a leak, but not in the usual spot like before. I think it's the door seal and was related to the way the wind was blowing while it was storming. The driver's side was dry for most of the day, but after a while it started seeping a bit. No puddle, just dampness on the floor mat. It would appear that I made at least some progress. Looking under the dash I see absolutely no leak on the passenger side. And it's literally impossible to see under the driver's side. Steering wheel, stick for the 4 speed and the '70 transfer case stick that bends over that way. I will probably try more windshield sealing and see what happens.
Attached Images
  
zac is offline   Reply With Quote
Old 05-19-2018, 02:52 AM   #18
toolboxchev
Registered User
 
Join Date: Jul 2015
Location: 2nd left past the stump on a dirt road.
Posts: 2,629
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by HO455 View Post
I would get a friend and a hose then dive under the dash with a good light. I would bet there are holes in the cowl that are the culprits. So have the friend slowly move the hose around the cowl vent area while you watch for water. It can come in from the top or the side. The driver side is easier view unless you pull the jockey box. The link below has good cut away photos showing the common problem areas.
Good luck. Been through this myself.

http://67-72chevytrucks.com/vboard/s...d.php?t=721974
Someone hopefully will come out with the patch panels to recover those areas in the future. After reading through the link I have re thought my goals for the current cab.
toolboxchev is offline   Reply With Quote
Old 05-19-2018, 12:29 PM   #19
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,753
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by zac View Post
Update: I sealed the upper corners of the windshield. My truck has that stainless trim, I'm glad I did a search on this board before I tried to pry it out. I pulled the cowl vent piece off and realized I obviously had an issue with the antenna lead. So I sealed that up. I also found a gap in the cowl area, more on the passenger side than the driver's, so I sealed both of those also. Then I left the truck outside to get rained on while I did the rockers and cab corners on my '79. Of course it didn't rain until the last couple days.

The passenger side has a leak, but not in the usual spot like before. I think it's the door seal and was related to the way the wind was blowing while it was storming. The driver's side was dry for most of the day, but after a while it started seeping a bit. No puddle, just dampness on the floor mat. It would appear that I made at least some progress. Looking under the dash I see absolutely no leak on the passenger side. And it's literally impossible to see under the driver's side. Steering wheel, stick for the 4 speed and the '70 transfer case stick that bends over that way. I will probably try more windshield sealing and see what happens.
If you have the cowl off still you could also try putting a big light (like a 300 watt quartz) under the dash and after dark inspect the cowl for light leaks. It may not show really small holes but you may get lucky.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 05-20-2018, 09:42 PM   #20
mike16
Registered User
 
Join Date: Dec 2009
Location: bisbee, arizona
Posts: 1,529
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

its even a problem here in southern AZ where to tourist brochures claim we dont have any rain... I pulled off the cowl panel and discovered a few seams where the seal has all but dried and pulled away from the seam. white window seal calking will sort that right out. 3.99 at Ace and a 35 year guarentee.
mike16 is offline   Reply With Quote
Old 08-02-2018, 05:59 PM   #21
Bearhawg
Registered User
 
Bearhawg's Avatar
 
Join Date: Feb 2018
Location: Snellville GA
Posts: 104
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

I know, I'm resurrecting and old-ish thread..

Overwhelmed, discouraged, despondent, you pick the word, brother I got it. Started the install of my new Vintage Air and found it, cowl rust. Pretty bad. Got the kick panels and the floor to toe kick seam. I can go two ways, 1) stabilize the rust, patch it up as best we can with auto-body epoxy, close it up and keep it dry OR do it right and go broke. I say broke because I wont do body work for a number of reasons. Trust me, I've tried and it did not go well. Body work is best left to the craftsman. Anyway, just had to vent, no pun intended. This has not been a good day.
Bearhawg is offline   Reply With Quote
Old 08-02-2018, 06:33 PM   #22
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,753
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

How about sharing some pictures so we can better help you with your decision.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 08-02-2018, 08:23 PM   #23
custom10nut
Registered User
 
custom10nut's Avatar
 
Join Date: Apr 2015
Location: East Tn (In the heart of the Smoky Mtns)
Posts: 1,846
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by zac View Post
Ok, I've had some sleep and a couple minutes of free time, and I see some problem areas, both above the upper windshield corners. Something tells me the design of the rain gutters maybe directs water into these areas in certain situations. The area with the pinhole is the driver's side and it has the worse leak. Apparently all the focus I put on the cowl area somehow made me miss this, although I'm sure I looked at this area and I don't remember it looking like this. The truck has been sitting indoors more or less abandoned for the last 3 years since I even thought about this. But sitting indoors in Kentucky for 3 years is like sitting outdoors for 30 in Colorado from a corrosion standpoint. I'm looking for a reasonable short term plan here to get me through to the part where the windshield comes out and repairs are made. I promise to report back what happens.
A sure way to stop it is to get all the rust out of the seam, and the go old school. Lead in the seams. I know it’s very uncommon nowadays, but still effective.
custom10nut is offline   Reply With Quote
Old 08-02-2018, 11:43 PM   #24
Bearhawg
Registered User
 
Bearhawg's Avatar
 
Join Date: Feb 2018
Location: Snellville GA
Posts: 104
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

Quote:
Originally Posted by HO455 View Post
How about sharing some pictures so we can better help you with your decision.
Will do. I took it to a local Restomods shop that has done some work for me before. I hope to post some pictures tomorrow. Thanks
Bearhawg is offline   Reply With Quote
Old 08-03-2018, 02:56 AM   #25
toolboxchev
Registered User
 
Join Date: Jul 2015
Location: 2nd left past the stump on a dirt road.
Posts: 2,629
Re: Has the Windshield/Cowl Leak Issue Ever Been Solved?

I have the same issue and doing a windshield very soon. Looking like something similar to the light brown rig posted above. I would like to see those pics also.
toolboxchev is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:07 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com