The lock on our Thule roofbox has jammed with key in it
I did a lot of research on forums about this and wanted to consolidate the results:
1. Don't use WD40, it attracts dust and grime later, use Silicon Spray or graphite dust
2. The main reason I'm posting, once it's free to open, lubricate behind the sliding locking bars with Silicon Spray, this helps A LOT.
3. Also consider what I did which helps 99% of the rest of the way: buy a couple feet of PVC, large enough to cover the sliding locking bars, cut it in half the long way, attach it to the box over the locking bars (I drilled holes and used zip ties).
The only remaining issue I have now is if I pile stuff too high and it puts upward pressure on the box lid, so don't do that. ;-)
As to the PVC, I think it was 1", and in fact it was not really big enough to completely cover the locking bars, so I didn't tighten the zip-ties down all the way, if I did it again I'd get bigger pipe or heat it and flatten it out a bit, but I just tested this setup on a 1200 mile trip and it worked great, noticeably smoother opening and closing.
on Oct 27, 2019