help with leaky trap arm

[norm6269]

Took apart the p trap and arm looking for the top of my wifes lip stick and I noticed that the trap arm just twisted out, no threading or slip joint nuts. No previous leaks either. I put everything back together and not I have a slow drip leak from the point where the arm is fitted into the wall...I'm stumped

 

[phishfood]

You probably need to replace the rubber compression washer behind that nut.

 

[norm6269]

Ok I will take a look at that, the nut does not budge, and it did not leak before removal.

 

[phishfood]

Tap on the sides of the nut with a hammer. This will help to loosen it

 

[norm6269]

That was the fix, much appreciated