Tightening Stair Bolts

I had this happen. I used a nut spliter to get the old nuts off and chased the threads then replaced the nuts.

If you can safely heat the nut with a propane torch that might do it.

The bolts that hold the steps to the floor have a round flat head with a square shoulder under the head, similar to a carriage bolt but with a flat head, then the floor covering is put down over them. They are driven into the hole so you can tighten them from the underside. I found new ones at a hardware store, but it's been a few tears ago.

As far a PB plaster goes, it's not worth the price of the little straw that comes with it. Go to Kano labs and order a can of AreoKroil, and a can of Silikroil. You'll never use PB blaster again, this stuff works!

PB Blaster or Liquid Wrench is what I always use to free up rusty bolts. I generally soak them several time over a period of a week before trying to break them loose. Bad thing is you may have to go in and replace the entire bolt. Since you don't have access to the other end.. Are you sure it is not one of these screwed into a floor joist.

Check the link.

Double end hanger bolts