Scribble a bit of pencil lead onto the contact/pivot points, one at a time, and test to see if it stops the creaking (just poke the pencil tip in and rub it on the spot without disassembling anything). Start with the pivot points, then spring hooks etc. When you find which one(s) was creaking you can then decide if further action is required.

Is it a 'creak' from metal scraping on metal or a vibrating/creaking spring noise from when they're being stretched?