Spent an entire Saturday chasing a leaky shower valve

Pulled the old single-handle Moen out and thought I'd have it swapped in an hour... turns out the supply lines were corroded onto the shutoffs. Three trips to the hardware store and 7 hours later I finally got it sealed. Has anyone else dealt with those stubborn old compression fittings that just won't budge?

3 comments

3 Comments

corap211mo ago

Used to think all you needed was a big enough wrench and some muscle to get those things off, but after my own 5 hour shower valve nightmare last spring I totally get it now. I ended up having to cut the old supply lines with a hacksaw because the compression nut was basically fused to the shutoff from years of hard water buildup. A little heat from a propane torch and some penetrating oil would have saved me two trips to the hardware store and a lot of swearing.

reese_lee91mo ago

Funny thing about the heat trick, you actually gotta be careful with it on compression fittings near shutoffs. The brass compression ring and the nut expand at different rates, so if you heat it too much you can crack the shutoff body itself. I usually try a good penetrating oil soak first overnight, then a quick blast from a heat gun on low just to warm it up, not get it glowing. Saved me from having to replace the whole shutoff valve once when I got carried away with a torch.

karenb971mo ago

I remember reading somewhere that heating up a brass compression nut can actually mess with the temper of the metal if you get it too hot, making it softer and more likely to strip out when you try to turn it. Was also told once by an old plumber that a quick shot of PB Blaster followed by a sharp tap with a hammer can break the corrosion seal without any heat at all. It's one of those things where a little knowledge goes a long way before you grab the torch.