Bathroom Sink Drain Repair

Remove the tail piece and the trap on the bathroom sink.
Replacing the PVC trap and tail piece may require you to cut the trap with a tubing cuter or a hacksaw.
Measure the tail piece, cut it to size.
Make sure when you put the nuts on with washers that you use some sealant.
After it is all together run the hot water and tighten the nuts again.
The hot weather softens the plastic and you should be able to tighten the nuts again.