I have a brass tube for water coming into a toilet in my very old farmhouse. The shut off valve failed and I had to cut the tube and am now trying to fix it... to no avail. We are three days without water in the house and the kids and I are going stir crazy without showers. I can't seem to find a 5/8 OD 1/2 ID fitting, shark bites don't work and regular compression fittings don't either, as they are all made for copper pipe these days. Can someone help me find an unthreaded, weldable cap for this stupid thing? I have three or four months til the new house is done, I just have to make it til then... Thanks!
Since this water line feeds into a toilet there is less concern about the type of repair used as a temporary fix for this situation. You should consider getting a suitably sized rubber pressure hose that can slide over the brass tubing and secure it in place using one or two gear type hose clamps.
On the other end you can adapt the hose to replacement valve as needed even if such valve is left somewhat free handing for the few months it is needed.
It comes in a size for 5/8" O.D. with 1/2" NPT threads so you can put a standard 1/2" pipe cap on it. Make sure you clean the brass pipe first so their is no leftover paint or dirt. Use teflon tape to seal the threads on the NPT side.
You should be able to find this fitting at a big box store but if not, have Amazon overnight you one.
If you are sure that the 5/8OD is the exact size of the tube you are working with, then that is the size of standard copper tubing used today. They do sell compression fittings that size. If this tubing is not that exact size you may have tubing 1/2" OD or 3/4 "OD. Copper water tubing comes in sizes 1/2", 3/4" and 1" ID, while refrigeration tubing comes in sizes 1/2", 5/8", 3/4", 7/8",OD.