Thanks to a Corvette Buddy I now have an original 307 expansion tank cap. It's in good shape, however the thin metal on the underside is pitted and missing small sections. Has anyone replaced this component? What was it's function. Do I need to worry about it? It seems if I do need to replace it the trick will be to get a rivet that matches the original, any suggestions? Jerry
-
-
Re: 307 radiator cap restoration
Jerry - I see nobody jumped on this one.
Yes, this piece can be replaced but typically the stainless steel piece from an "new" AC RC-15 or RC-26 is used; because finding an original aluminum piece is rare because of just what you have observed and then if the aluminum piece is still good why take the cap apart.
The thin metal piece directly under the cap on the #307 and RC-26 radiator caps produced in the mid 60s was aluminum and it not uncommon the this piece eroded away. I expect it initially offered some tension when installed to help keep the cap in place; but these caps also had a fiber gasket and that would also help keep the cap in place on the expansion tank. Some might suggest that the aluminum piece is in the cap to prevent the zinc plated steel cap from being in direct contact with the aluminum expansion tank and setting up an electrolytic reaction, but with the fiber gasket in place contact with the underside of the cap is greatly reduced and the two aluminum surfaces are not in direct contact, but the part of the cap that holds the cap to the tank neck is still in direct contact; so aside of providing tension to help hold the cap in place; I'm not clear that it has another function and if it does someone will let us know, I'm sure.
If everything else is good on the cap, the cap should be fine. BTW, I'd make sure the fiber gasket was in good shape.
Yes, the "rivet" is the trick.
Hope this helps and good luck with the cap, Pete
Comment