On 11 Apr , 2023, at 3:42 PM, Dan N <dn92610@GMAIL.COM> wrote:
> 
> they become hard rubber. No product
> can get them swell anymore to seal the leaks.

        Might not necessarily be so,,, There is a product called Super Rubber Rejuvenator

it quite easily transforms Rock Hard Rubber Offset PrintingPress Rollers back into the nice

Soft Pliable rollers that they were originally so I don’t doubt that there might very well be

a chem’ that could do a simsilar trick on rubber H2O Gaskets ~ & there are also additives

for Transmission Fluids that do that as well ~