69 Radiator Supply Tank Problem

[Michael C.]

Call it what you prefer - radiator supply tank, recovery tank, surge tank... it's the long black tank with radiator cap, mostly hidden on the right side of my BB with A/C. Copper/brass construction.

As you can see in the photo, the top surface of the filler neck is "malformed." I have no idea how this would have happened, but the result is that there is a very poor seal between the filler neck and the secondary seal of the cap. If the radiator "burps" for whatever reason, fluid spills out around the cap as well as out the overflow hose.

Any suggestions as to how to prevent this? I'm reluctant to try to bend the distorted surface back into shape and risk more damage to this $400+ part. I wonder if sealant that remains pliable after curing could be applied top of the neck. I've tried a cap that has a rubber secondary seal, but that doesn't completely eliminate the problem. Any suggestions for a sealant that would remain pliable and resistant to antifreeze and heat?

Thanks
Mike
RecoveryTank.jpg

[David M.]

Re: 69 Radiator Supply Tank Problem

It's brass. Small gentile taps with a small ball peen and several different pieces/shaped/size of wood say a paint stir stick or maybe some harder wood that won't shatter.

Round off the squared end of the stick or wood piece.

Lay the rad on a flat surface and gently start to shape it back to flat. It doesn't need to be 100% flat just close. This isn't the sealing surface but if it's that far out of whack it will affect how the cap aligns with the lower seal.

What does it look like down in the neck where the sealing actually takes place with the cap gasket?

I guess the first question is, is this a new unit still under warranty? If so don't touch it and contact the supplier for what's next...even if you think too much time has elapsed since the original purchase.

The primary (lower) seal is where the system pressure is held against the caps-rated spring pressure. The secondary seal allows the coolant to pass out the overflow if a high-pressure event occurs.

[Michael C.]

Re: 69 Radiator Supply Tank Problem

David, thanks for your thoughts. The opening in the neck for the primary seal looks fine. This is the original tank. I might have to resort to some gentle taps here and there.
Mike

[Richard M.]

Re: 69 Radiator Supply Tank Problem

Mike, If you have a very small Hobby-Type C-Clamp, using a heavy flatbar on top like you have there, you should be able to reform under the lip to get it flat.

Like this.....
RecoveryTankClamp.jpg

[David M.]

Re: 69 Radiator Supply Tank Problem

Richard,
Good idea with the C clamp. Small vice grips could work as well. Vice grips come in many different smaller sizes with curved jaws etc...I think they make a size 5 or 7 mini welding set that has little feet on it. I know they make large welding grips. I have some.

Do a google for both items mentioned here. Neither should be expensive.

[Michael C.]

Re: 69 Radiator Supply Tank Problem

Richard, send me one of the C clamps you inserted into my photo and I'll put it to good use. Good idea. I'll see what I can find.
David, Vice grips also might work.
Thanks guys.

[David M.]

Re: 69 Radiator Supply Tank Problem

Something like this....You may want the mini size 4, 5, & 6. Not sure how large of a throat area you need? You may want the larger sizes? Go to HD or Lows and look.

They come with and without the feet. The pliers without feet will allow tighter accessibility. The ones feet with the feet will spread the load and not distort the metal as much.

[Michael C.]

Re: 69 Radiator Supply Tank Problem

David, your tool suggestions have real potential. The biggest challenge will be accessing the right places because of the tight spaces due to the neck lip and overflow tube output.