enter image description here I have a Packasport fiberglass car top carrier with a cylinder lock (outside view above). The key has been lost. I ordered a new lock/key set from Packasport but am unable to remove the old one - the locking nut is rusted on. I've tried Linseed Oil and WD40 and still doesn't work.

My latest idea is to drill through the locking nut that is right next to the fiberglass wall of the carrier (drilling parallel to the wall, perpendicular to the surface of the locking nut) to create a gap and then just wedge the nut off using a chisel. I don't care about damaging the existing lock but I don't want to damage the fiberglass. However, when I tried this the drill would just slip right off the (very thin) nut surface.

Any ideas?

These car top carriers are expensive (about $1000) so worse comes to worst, I'll probably just live with not being able to lock it any longer.


Here's what it looks like on the inside:

Packasport Car Top Carrier with rusted lock - note locking nut is the large one right next to the white fiberglass surface

  • Can you use a rotary or reciprocating saw instead of a drill? What do you need to keep in the picture? From left to right. Fiberglass, Hex, threads (lockset?) Washer, threads?
    – treeNinja
    Aug 22, 2014 at 21:27
  • Just the white fiberglass needs to be undamaged. All the metal pieces in the picture can be destroyed. The goal is that if I could remove that large locking nut on the left right next to the white fiberglass, I could slide out the whole cylinder and I'd be left just with a 3/4" hole in the fiberglass. I put in the new cylinder set I have, with a new locking nut against the fiberglass, and I have a new lock on the carrier (unshown is a hook I removed that attaches on the right of the threaded screw - it's what actually engages the lock as the cylinder turns.)
    – Mike Kelly
    Aug 22, 2014 at 22:05
  • Best thing I have used is called breakfree Aug 22, 2014 at 23:18

3 Answers 3


Why not leave the lock in place, drill a hole for a new lock and move the locking mechanism a few inches to the right or left?


I'd use an angle grinder with a thin cutoff wheel and basically just cut either the locking nut or the whole cylinder in half. If you're reasonably careful, you should be able to do this and barely touch the fiberglass (if at all). You're much more likely to cause cracks or other damage if you are putting torque on something, and it's much easier to have fine control over an angle grinder than a reciprocating saw or a drill.

  • Instead of an angle grinder, I'd take a Dremel-like tool with an abrasive cutoff disc to the locking nut.
    – mike
    Aug 23, 2014 at 2:13
  • @mike - That would certainly do the trick too - angle grinder is my bias because the cutoff wheels are so cheap. The key is certainly the cutoff disc though.
    – Comintern
    Aug 23, 2014 at 2:17

If you live near or have access to a good tool supplier, Sears,Auto Zone etc. The best tool for the job in my opinion is a nut cracker. It looks similar to a pipe/tubing cutter with a chisel tip instead of a cutting wheel. Because there in no rapid motion of the tool the risk of damaging the fiberglass is reduced. they generally come in two sizes and cost under $20. Once you have one you'll find lots of use for it. My favorite tool for removing toilet hold down bolts without damage to the porcelain.

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