Can you loosen a pipe threaded fitting without causing a leak?

[McFly]

I have a situation where I have to change the angle of a 90 degree fitting (AN/pipe) to get proper clearance. I need to rotate the fitting about 5-10 degrees if the direction that will loosen the fitting (left).

Can you loosen a pipe thread fitting without causing a leak (assuming that it will still be very snug of coarse)? It will be a lot of work if I have to take the fitting all of the way off, re-lube, and reinstall (in case you were wondering) . Thanks.

[osxuser]

Originally Posted by McFly

I have a situation where I have to change the angle of a 90 degree fitting (AN/pipe) to get proper clearance. I need to rotate the fitting about 5-10 degrees if the direction that will loosen the fitting (left).

Can you loosen a pipe thread fitting without causing a leak (assuming that it will still be very snug of coarse)? It will be a lot of work if I have to take the fitting all of the way off, re-lube, and reinstall (in case you were wondering) . Thanks.

Nope, it'll probably leak.

[Mr. Mikey]

It really depends on how you sealed the threads before you installed the fitting.

If you used teflon tape (that you aren't supposed to use on fuel lines), you might get away with it. If you used a thread sealant that sets up, like blue RectorSeal, then probably not.

I used to work with natural gas and liquid propane piping. Backing out a pipe thread is asking for a leak. Murphy's Law dictates that it won't leak untill you are in cruise flight above a mountain or large body of water.

I'd redope the fitting and pay close attention to where I need to face it when reinstalling. It's more work, but why ask for trouble?