as easy as it is to fab and install, the spring [or whatever you want to call it] in the lower hose can't hurt anything, especially if you have a long section of straight hose, and if there may be some trouble getting all the air out of the system. just my opinion, and i could be [more than likely !] wrong. wouldn't be the first time !
Pieces of rusty coil have been known to find their way to water pumps, sharp ends have pierced hoses...it IS possible for things to go wrong. Stainless steel is advised.
I once used an antenna-----that was a beech to coil up!!!
