If you could get this inserted with the valve slightly cracked open, maybe this would work?

https://www.petersenproducts.com/category-s/1957.htm

and a cheaper version:

http://www.homedepot.com/p/CHERNE-3-in-Single-Size-Test-Ball-Plug-270032/100160348


Last edited by RAH; 10/23/17 07:02 AM.