I have a rusting screw secured with a U-style spring nut in a very tight and difficult place. The screw secures one of the fog light assemblies to the bottom of my Forester's bumper. Here's front and side views:

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Trying to unscrew the screw using just a 10-mm wrench makes the whole thing rotate, bending the plastic. It is impossible to grip the nut, as the space is too tight for a standard pliers. Applying too much torque will surely crack the plastic. I sprayed with generous amounts of oil (WD40 style), but to no avail.

Is there a tool I can use to remove this stubborn screw?

  • Try penetrant (I like PB Blaster) and let it soak for at least a couple of hours. Sometimes heat can help although you will need to be careful of the plastic. Sometimes these are simply "welded" and cannot be budged. You'll need to try to cut it off and replace it.
    – jwh20
    Jul 19, 2021 at 17:28

1 Answer 1


Actually, see if you can tighten it ever so slightly first, then hit it with the penetrant/rust agent. Let it sit for the couple of hours, then hit it with some type of thicker lubricating oil. When that's on there, then squeak it back and forth to work in the oil a little bit. You should be able to work it out that way. Heat isn't going to work very well due to the plastic, but I'm sure you've already figured this out. You can also through some type of pliers on the J-nut (yah, that's what it's called) to hold it and support/protect the plastic.

  • Thanks. I got a can of PB Blaster penetrator today, will give it a chance. Hopefully it works better than the thin lubricant (think WD40) I used before. J-nut or U-nut? I guess we'll know when I manage to get that POS out...
    – ysap
    Jul 20, 2021 at 14:21
  • @ysap no clue why they are called a "j-nut", but that's what they call it. Jul 20, 2021 at 18:38
  • My short research - it depends on the "rear" plate. It is either short or full length. Short is "J" shape, full is "U" shape.
    – ysap
    Jul 21, 2021 at 14:16
  • BTW - PB Blaster did not make to much an impression on the nut.... But I figured out I can just cut the black plastic tab of the light assembly itself (which is the part that is secured with the screw), and thus have much more space to use pliers or any other tool.
    – ysap
    Jul 21, 2021 at 14:18

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