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so i removed the heater box and i poured water around the windshield and in the cowl, checking for water after each time i placed new water.

nothing was leaking for a few minutes but after a while there was a drip. I cannot tell which was the culprit

seems to be coming in from this seam. ( see pic )

I was going to silicone all the joints around the cowl and wherver I can reach as the first line of defense.

i dont want to replace the windshield so if its the windshield its going to have to stay for a while. Its garage kept.

but I would love to fix this leak. this is me laying in the passenger floor under dash, looking up and left

757339
 

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1968 coupe, 1968 vert, 1966 coupe
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Sorry to tell you but that is most likely your cowl which is something that in my opinion should be replaced even if the cars garaged. Because over time your floor, firewall, the rest of the cowl and mother things will fall victim to the rust. Silicone around the leak is only going to make things worse. I’d start with cleaning out the cowl and seeing how bad it is.
 

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Discussion Starter #5
Sorry to tell you but that is most likely your cowl which is something that in my opinion should be replaced even if the cars garaged. Because over time your floor, firewall, the rest of the cowl and mother things will fall victim to the rust. Silicone around the leak is only going to make things worse. I’d start with cleaning out the cowl and seeing how bad it is.
The car was just painted. I’m not pulling the cowl out now.
There is no rust anywhere except where it was dripping on the floor board which I fixed.

I was hoping silicone would divert the water to the outside of the car. Probably hopeful thinking.

the car is solid besides this. I’ll just use spray wash and carry some towels for when it rains.

Should I pour water into the cowl to confirm it’s the cowl ?

thanks for the input
 

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1968 coupe, 1968 vert, 1966 coupe
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The car was just painted. I’m not pulling the cowl out now.
There is no rust anywhere except where it was dripping on the floor board which I fixed.

I was hoping silicone would divert the water to the outside of the car. Probably hopeful thinking.

the car is solid besides this. I’ll just use spray wash and carry some towels for when it rains.

Should I pour water into the cowl to confirm it’s the cowl ?

thanks for the input
Yes pour water into the cowl to make sure that’s your problem maybe you’ll get lucky and it’s not but I’m guessing it is however it looked pretty clean under there...is the inside of the cowl clean? Meaning when you poor water into the cowl it runs out under the fenders. If nothing does that means it’s clogged!
 

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If the leak originates around the windshield and goes along a weld seam, you may be able to remove the trim and be sure all gaps are filled with the 3M Bedding & Glazing Compound, check for leaks then re-install the trim.
I refused to tear apart a very solid and rust-free car to fix a pin hole or crack where a small piece of seam sealer allowed a few drops to come in, so I made a 360° sprayer and used POR-15 to coat every surface inside the cowl. That did an amazing job and the car is now leak-free, even with car washing or gallons of water dumped in the cowl vent.
 
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Tape some saran wrap over the cowl grill, then hose the windshield. Don't like your chances though.
 

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Discussion Starter #9
If the leak originates around the windshield and goes along a weld seam, you may be able to remove the trim and be sure all gaps are filled with the 3M Bedding & Glazing Compound, check for leaks then re-install the trim.
I refused to tear apart a very solid and rust-free car to fix a pin hole or crack where a small piece of seam sealer allowed a few drops to come in, so I made a 360° sprayer and used POR-15 to coat every surface inside the cowl. That did an amazing job and the car is now leak-free, even with car washing or gallons of water dumped in the cowl vent.
thanks to all for the info. cant wait to figure this out. How does one paint the inside of the cowl ? the car is painted so I cant paint from above.

do the windshield trims re attach easily ? Im hesitant to pop them off.

on a different note I have the door panels off because the passenger door handle is loose on one side. the nut is inside the door. the handles are in good shape Im concerned it will loosen again after I tighten it. what can I do to ensure it will stay tight ? I bought new panels and hopefully I dont need to remove them for a while, those clips suck.

while the door is exposed what should I do to the mechanicals of the door and window while its exposed

thanks
 

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How does one paint the inside of the cowl ?

Use a 360-degree spray wand from Eastwood or another painting supplier, create one on the cheap with a garden sprayer. I went cheap with a one gallon sprayer and a quart of POR-15 after getting the cowl absolutely clean.

do the windshield trims re attach easily ? Im hesitant to pop them off.

Easy is a matter of opinion, I guess. I've done harder things, that's for sure...

the passenger door handle is loose on one side...what can I do to ensure it will stay tight ?

Try a small lock or star washer, or just a drop of blue Loc-tite threadocker.

while the door is exposed what should I do to the mechanicals of the door and window while its exposed

This is a good time to be sure your windows are adjusted well, your rollers are all intact and well lubricated in the tracks, and the watershields are installed.
 

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thanks to all for the info. cant wait to figure this out. How does one paint the inside of the cowl ? the car is painted so I cant paint from above.

do the windshield trims re attach easily ? Im hesitant to pop them off.

on a different note I have the door panels off because the passenger door handle is loose on one side. the nut is inside the door. the handles are in good shape Im concerned it will loosen again after I tighten it. what can I do to ensure it will stay tight ? I bought new panels and hopefully I dont need to remove them for a while, those clips suck.

while the door is exposed what should I do to the mechanicals of the door and window while its exposed

thanks
If you ae careful you can remove the fender with out messing up your new paint job. Then to gain access to the cowl for cleaning cut it open like this.
757445

From your picture it looks like yours is leaking where mine was. Just a couple of pin holes. You have to make up all kinds of tools to reach inside and get all the surface rust out. Then use rust stop and coat everything inside. Let it dry good and apply a good sealer. Someone will jump in and tell you what is the best products to use. You have to stop the rust or it will continue to eat away.
It is a real pain to do but will be worth it in the long run. Rust just keeps eating away if you don't stop it.

yarb
757460
757461
 

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I didn't take the fenders off. I went from under the dash with the heater box and fresh air vent, with some brushes bent in several shapes and a goose neck vacuum attachment and finally my fingers all around the hats...used an old mobile phone to the video of what everything looked like inside...then used my sprayer with POR-15 to coat EVERYTHING from one end to the other. You can tape off the cowl vents really well so when you spray upward to the underside of the upper cowl it doesn't spray through. You also can tape off the vent grid and leave open a slot or two in the middle and spray some leveling sealer inside the entire width with the car jacked one side high and let it run all the way to the drain, then jack the other side and do the same. That will double coat the areas where water actually runs.
 
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