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Lower cowl rust repair

Gearhead72

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I'm working on a 1972 charger that I have owned since I was 16. Now almost 48
The car is not rotted underneath but I have a few trouble spots aside from needing quarters that I already have.
The lower cowl is rotted where the duct connects under the dash.
I'm contemplating drilling the spot welds and removing the upper cowl which is in perfect condition. I not sure If I can do the repair from inside the body once the dash has been removed.
Any information would be greatly appreciated.
 
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What your calling the lower cowl is actually the top of the firewall.
You could drill the spotwelds off the upper cowl & remove it if the windshield is out, cleanup everthing, repair/patch any rot & rust, prime/paint, then reassemble. Lots of problems in that area on these cars so many here have worked on this area.
Its hard to elaborate any deeper without looking at the problem face to face. Care to show us some photos?
 
I can't photograph the area in question. I only know about it because I used a camera scope to see underneath the cowl pan. The upper firewall is rotted around the openings for the heater box. Part of the curb or upward bent metal is gone in one spot on each side.
The windshield is out and I'm going to remove the dash and everything inside the firewall.
 
Be aware there is factory lead where the cowl panel meets the A pillars.

I call those areas the OP is referring to "vent stacks".

SUPER common problem on 71-74 cars, and not terribly easy to fix.
 
It sounds as though you are going to need a firewall. Thats where all heater box components are located. The cowl sits on top of the FW & houses the wiper gear. The fresh air vent is in the top of the firewall, under the cowl.
If you've got as much rust as it sounds, getting the cowl off should be 1st priority. It should be easy to remove the dash with the windshield out.
Do a little work & a few hours drilling spotwelds. Expose everything & grab some pics & post them up so we can give some quality input. Its hard to help based on what we know here so far.
 
Be aware there is factory lead where the cowl panel meets the A pillars.

I call those areas the OP is referring to "vent stacks".

SUPER common problem on 71-74 cars, and not terribly easy to fix.
 
Thanks for the heads up about the led. Not really a problem but I didn't know to look for it . I'll get pictures when I get the dash and heater box out.
Not sure when I will get to it.
What do you think about possibly patch it from inside the body. This is a 72 se not Really rare or valuable. But I want to do everything right because I will be investing a good deal of money by the end of the project. Not to mention lots of time.
 
You cant "properly" fix that area from just the inside of the car.
If you are seriously considering keeping or fixing properly, rust has to be removed, patched, primered & top-coated from both sides...
 
P.S.
It WILL take lotsa time to fix rust.
Thats why shops are so expensive.
Tools are available, & tech is here for you through the rough stuff...
Something tells me you may not be ready for the challenge in front of you, though....
I hope you prove me wrong.
 
P.S.
It WILL take lotsa time to fix rust.
Thats why shops are so expensive.
Tools are available, & tech is here for you through the rough stuff...
Something tells me you may not be ready for the challenge in front of you, though....
I hope you prove me wrong.
I know what I am in for. It's been 20 years since I've done a project like this. But I'm better equipped and have the shop space to take my time and do it right. I'm getting good information from this forum. Also I have friends that can help with it if I need but they all have different options and ideas. They just don't know Mopars
You guys are a great help and are very appreciated
 
I hope yours isn’t this rusty. Be prepared if you get started... Pics man, We all like pictures around here.:xscuseless:
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I hope yours isn’t this rusty. Be prepared if you get started... Pics man, We all like pictures around here.:xscuseless:
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After seeing your pictures I'm decided that removing the cowl which was my first instinct but was talked out of is the best thing to do.
I'm guessing mine looks close but I have to get more apart. The status of your car is the direct I am going. Engine out dash and heater box out. Then I'll start with the cowl and firewall then address the small issues with the roof skin at the windshield. I will get pictures when it's disassembled. Probably in the fall.
 
After seeing your pictures I'm decided that removing the cowl which was my first instinct but was talked out of is the best thing to do.
I'm guessing mine looks close but I have to get more apart. The status of your car is the direct I am going. Engine out dash and heater box out. Then I'll start with the cowl and firewall then address the small issues with the roof skin at the windshield. I will get pictures when it's disassembled. Probably in the fall.
Sounds like a solid plan.:thumbsup:
 
Mine was a nightmare to do. Had to peel back the cowl in spots to gain access to the firewall. Took many pieces like a puzzle. Afterwards i used seam sealer in between the two only leaving the drains open. Then painted it inside. Looks good after the skin of bondo was applied.

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I hope yours isn’t this rusty. Be prepared if you get started... Pics man, We all like pictures around here.:xscuseless:
View attachment 1130257 View attachment 1130258 View attachment 1130259 View attachment 1130260
View attachment 1130261
Can the cowl be removed without disturbing the inner fenders? My rust is not too bad but I could find more problems once the cowl is off.
I probably saved it for the most part because I used to take the plastic screens off and was out the debris and rotted leaves at least one a year from about 1988 until the early 2000s.
 
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Been there, done that. I used a donor cowl that was better than mine.

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It took time but was worth it. I coated the inside with 2K primer sealer and then topcoat with Satin Chassis-black for a hard water repellant coating.

RGAZ
 
Been there, done that. I used a donor cowl that was better than mine.

View attachment 1130774 View attachment 1130775 View attachment 1130776 View attachment 1130777

It took time but was worth it. I coated the inside with 2K primer sealer and then topcoat with Satin Chassis-black for a hard water repellant coating.

RGAZ
Looks like an older B body. The 72 firewall and cowl is different. Same amount of work though. I wish there were as many new parts available for the gen 3s
 
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