The upper grommet (302497) has predictions which engage holes in the casting. The long tool used to install these fit the inside of the grommet and is ground away on opposite sides to allow these projections to retract. When in place , it is then twisted to push these projections into there respective holes. A lubricant makes this easier. but some oils react with the grommet to bond it the the copper making future removal difficult. The upper grommet can be carved away to get at the copper tube. When the new grommets are in place make sure the water tube is the proper length and has NO rough edges. I like to use KY jelly as it does not react to rubber. Be sure everything lines up properly when installing the lower unit . . . 😉
Gale mod 12S13
