Difficult to access bathroom sink, leak at ballrod

[Brianrzq1]

I recently cleaned all of the gunk out my bathroom sink drain. After putting the ballrod back in, I noticed a leak that occurs when water goes down the drain. There is a little bit of play between the ball and the screw which I think is where the water is leaking. I tried the same ballrod on a different sink and it works fine. It seems like the problem is with the pipe that the assembly screws onto. To make it more difficult, it's really tough to get to the back of the sink the way that it was installed. Anyone know a way to fix this without putting a new pipe in?

 

[Brianrzq1]

In case you were on the edge of your seat waiting to hear the solution for this one....

The little bit of play between the ball and the nut where the water was leaking was caused by a missing slip joint washer. It must have accidentally gotten thrown out when the drain was de-gunked. I pulled the slip joint washer from one of my other sinks, and the leak is fixed. Now I just need to find a new washer for the other sink......