What is the easiest and best way to fix a leaking shut-off valve on a toilet?
Replace it there fairly cheap.Usally all you need is a wrench an pipe thread tape and a new shut off valve bably less than 20 bucks total.Just turn off the water an flush the toilet.Place a pot under the connection so it will catch any remaining water as you loosen the connection.There are 2 large nuts at each end of the shut off valve.Turn them conter clockwise to loosen an clockwise to tighten.Wrap the threads with pipe thread tape on both ends before installing the new shut off.Its probably one of the easiest do it yourself plumbing jobs there is.Once you have the new shut off installed an tightened turn the water back on an check for leaks.If it is leaking you may have to tighten your connection a little more.Good luck,I hope this helps.
Take out the old one. it is easy it just slides up the over flow tube go to a hardware store and get a replacement ball valve (Ballcock) they are just a couple bucks.slide the new one on! Take the old one when you go to get the new one.
