Radiator and Drain plug/Petcock - Help Needed

Nate Dynamite

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So.. as you can see in the photo I took, that today I not only managed to get out the petcock, but also the nut that was soldered into the radiator.

Originally, a few months ago, the petcock end cap broke and flew out when I was tightening it back after a coolant change. I was like, “oh darn, I’ll take it out and go get a new one from the auto parts store.” Well, no, the f**k*r stripped. Even with penetrating oil and WD40, no luck. So today, months later, I have finally gotten around to work on it again. I tried using a propane blowtorch to loosen it, but well I loosened the wrong thing initially.

I don’t know what that base plug part is called, but what I do know is that, I have stripped the edges of it and the drain plug nut is even more stripped and still hasn’t come off even after individually being heat blasted and sprayed. I’m guessing the thing corrosion-welded together.

I’m not sure what to do to be frank. And I can’t afford a new radiator at the moment. But maybe a used? I’d like to be able to find the right parts and resolder/braze back into place.

This is out of a 1966 Plymouth Fury III with a 318 in it.

Any thoughts, suggestions, etc. would be appreciated.
Thank you

IMG_7047.jpeg
 
Get the petcock out of the soldered nut. Then solder that part back in the radiator. Install a new petcock. Don't overtighten it.

Throw the WD40 away and don't bring anymore home. It's a garbage product.
 
Throw the WD40 away and don't bring anymore home. It's a garbage product.
^This^.

Get the petcock out of the soldered nut. Then solder that part back in the radiator. Install a new petcock. Don't overtighten it.
If you haven't stripped the threads out, this is what you need to do. Heat the soldered nut up with a propane torch and I'll bet the petcock will come out. Heat and cool a few times if needed.

Then wire brush the area, apply flux and solder the nut back in place. Be careful with the heat as you don't want to melt any other solder out. If soldering isn't something you can do, you may be $$ ahead to find a radiator shop to fix it.
 
I know you said money is tight so this may not be an option; coincidentally there is a fellow member selling one from his 1966 Fury with 318.

For Sale - 1966 Fury 318 radiator

I love WD-40 for cleaning carbon, keeping my tools clean and rust free and lubricating metal when pressing. Not the right tool for breaking threads though.
 
the core is soldered to the tank ...too much heat and you'll melt that joint and have a real leak...
 
Get the petcock out of the soldered nut. Then solder that part back in the radiator. Install a new petcock. Don't overtighten it.

Throw the WD40 away and don't bring anymore home. It's a garbage product.
^This^.


If you haven't stripped the threads out, this is what you need to do. Heat the soldered nut up with a propane torch and I'll bet the petcock will come out. Heat and cool a few times if needed.

Then wire brush the area, apply flux and solder the nut back in place. Be careful with the heat as you don't want to melt any other solder out. If soldering isn't something you can do, you may be $$ ahead to find a radiator shop to fix it.
Thank you for the advice, greatly appreciated. However, I would like to further clarify:
Initially when I broke the darn petcock, and mangled it, I sprayed it with WD40. Which I understand, and especially now, realize is useless and pointless. That was back then.
Yesterday I used PB Blaster penetrating oil, and left it soaking with a few sprays. I cleaned around the threads of the drain plug/petcock, and base piece/core, (with a wire brush), then applied heat with a propane torch. Which then lead to me heating up the base too much and loosening the solder and pulling the whole thing.

I will not use WD40 on the future for trying to break something free, thank you for that advice.

No, the threads are not damaged. The nut part of the drain plug is stripped and I’ve had a hell of a time trying to wrench it off.
I’d like to resolder the piece,
But my biggest difficulty is that I have been unable to grip either the nut or the core in general to extract the petcock.

I think when I tried getting it out months ago I might’ve tightened, now I can’t get it broken loose, even going the right direction.

I’m at a bit of a loss, kicking myself, and scratching my head on how I can get the stupid thing out of that core piece.

Any ideas folks?


If I can’t find a radiator shop, and I can fix it myself, I’m might take up that offer for that rebuilt radiator.



Ps, love this community. So quick with help and ideas
 
Thank you for the advice, greatly appreciated. However, I would like to further clarify:
Initially when I broke the darn petcock, and mangled it, I sprayed it with WD40. Which I understand, and especially now, realize is useless and pointless. That was back then.
Yesterday I used PB Blaster penetrating oil, and left it soaking with a few sprays. I cleaned around the threads of the drain plug/petcock, and base piece/core, (with a wire brush), then applied heat with a propane torch. Which then lead to me heating up the base too much and loosening the solder and pulling the whole thing.

I will not use WD40 on the future for trying to break something free, thank you for that advice.

No, the threads are not damaged. The nut part of the drain plug is stripped and I’ve had a hell of a time trying to wrench it off.
I’d like to resolder the piece,
But my biggest difficulty is that I have been unable to grip either the nut or the core in general to extract the petcock.

I think when I tried getting it out months ago I might’ve tightened, now I can’t get it broken loose, even going the right direction.

I’m at a bit of a loss, kicking myself, and scratching my head on how I can get the stupid thing out of that core piece.

Any ideas folks?


If I can’t find a radiator shop, and I can fix it myself, I’m might take up that offer for that rebuilt radiator.



Ps, love this community. So quick with help and ideas
Here's what I would do.

Clamp the brass fitting in a vice (see the yellow arrows). Take a drill about the size of the hole and drill completely through the fitting in the direction of the white arrow. It should drill pretty easy, but go slow, pulling the drill out to clear the chips often.

Once you get it drilled through, get a little larger drill and drill from the other direction (green arrow). 3/8" is as big as you want to go and you don't want to drill any "deeper" than the length of the petcock inside the rad fitting.

The fitting will now just be a thin shell. It should screw out now. Maybe a little heat might be needed but be careful.



Fitting.jpg
 
Here's what I would do.

Clamp the brass fitting in a vice (see the yellow arrows). Take a drill about the size of the hole and drill completely through the fitting in the direction of the white arrow. It should drill pretty easy, but go slow, pulling the drill out to clear the chips often.

Once you get it drilled through, get a little larger drill and drill from the other direction (green arrow). 3/8" is as big as you want to go and you don't want to drill any "deeper" than the length of the petcock inside the rad fitting.

The fitting will now just be a thin shell. It should screw out now. Maybe a little heat might be needed but be careful.



View attachment 719077
Yes sir . Thank you, cheers!
 
How about just soldering the thing back in and forget about the petcock being a drain. Just pull the lower hose when you want to drain the system. That would be the easiest/cheapest way to go until you can do it according to Hoyle.
 
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