Honestly, since you got it that far down, why not make it right? They worked fine when all the componets are in good shape. The checkvalve is nothing more then a plain ole Poulan duckbill valve and those are good for about 20 years it seems. :hmm3grin2orange:
I forgot that I photoed my Ridgid branded version when I done it some time back. Pictured are the connector, the duckbill, the line in the tank and the duckbill with a pice of larger hose over it. Thats all thats needed.
There was another type of check valve that was used that was a flat piece of plastic with a rubber flap type valve on it but that was a early version and NLA anyway.