help with leaky compression fittings

wombosi · 01-22-2009, 09:45 AM

So, just put all my plumbing back together, a million sweated joints, none of them leaking a drop, shutoff valves on sink and toilet also leak free.
i have chrome looking supply lines to the tub, that come down into a brass compression fitting, which is threaded onto a copper adapter.

the end that goes into the tub faucet just has a rubber washer with a nut behind it. no leaks from that end.
the other end has a little brass washer that's slightly wider int he middle, with a nut behind it, apparently meant to be compressed onto the supply line and seal it.

the hot side seems to be OK. the cold has a slow bead drip. i've wailed the down to the point that the entire supply line starts to turn, along with all the copper below it.

there must be some kind of better system? can i use a rubber washer instead of the brass one?
any cleaner, tighter way to get from copper to supply line?

much appreciated!

bradnailer · 01-22-2009, 10:13 AM

If it is a true compression fitting, then you can back the nut off and wrap about five wraps of teflon tape around the ferrule. Pull the nut back down and button it back up. Make sure also that the ferrule stays seated in the top of the fitting while you tighten back up the nut.

Chemist1961 · 01-22-2009, 11:00 AM

Put a wrench on the fitting as well as the nut for best leverage. Then sqeeze them together holding the fitting still. I've never had to use tape and I'm not a plumber but for me the last 1/4 turn or so holding the fitting with one wrench levering to it with the nut always does the trick.

wombosi · 01-22-2009, 02:55 PM

Thanks a lot guys, that was helpful.

**Termite** · 01-22-2009, 04:01 PM

Putting tape on a compression fitting's threads isn't necessary. The seal is not made by the threads, it is made by the compression ring. If properly seated and tightened the ring should do all the work and the nut and threads simply serve to keep it tight.

Clean the pipe thoroughly and use two wrenches.

buletbob · 01-22-2009, 04:12 PM

I would agree with KC.
Remove the nut and inspect the ferule to see if its seated in the receiving portion of the connector properly if not you might have to cock the supply tubing slightly to have them mate up. then use the two wrench technique as described above. BOB

DUDE! · 01-22-2009, 04:44 PM

It must be an experiance thing, every time I use compression fittings, two wrenches, red in the face and that sucker will leak, of course after two or three times it will stop but seems like something is going to break before you finally get it tight. And seems easy to not be dead center on both ends, causing the ferrell to not seat properly.

wombosi · 01-22-2009, 09:43 PM

so, i took off the standpipe wiht the ferrule totally crimped onto it. not sure if i can reuse this as is? looks like it's seated properly.

i read that you're supposed to only hand tighten, the 1/2 turn with wrench? would be a total geyser.

i'm wondering, every old tub i see has copper lines running straight up to the faucet, with a little angled "ball" coupler brass looking thing.
can you still find these fittings? i find the compression fittings on the chrome pipes a real pain and on top of that they look like junk.

thanks.

drunknmaster · 01-22-2009, 10:19 PM

use telfon tape around the furrer about 3 times,if still leaks cut pipe are cut of furrel and start over it is not rocket scinec....burp

buletbob · 01-23-2009, 06:25 AM

Those ferules are not intended to be tightened to the point where you have to lay into them. get a new riser tube and feral hand tighten it together then tighten it with your wrenches about 1 to 1-1/2 turns turn water on if it leaks tighten it 1/2 turn at a time until it stops. I believe you over stressed the mating parts. or cracked the nut. once you get the feel for it you will have no problem in the future. BOB