Awakening an old post but the same issue. All four of my C5 X7 doors creak and groan. Have popped the lids off and found slutchy rusty muck as a poor grease substitute. Rear door hinges removed complete and (crudely) modified to add a grease nipple like so:
- 90° M6 grease nipple
In reality the metal is far too thin for an M6 thread. But it's just about hanging on in there so far. Position feeds grease into the top half (beyond what's visible with the lower cap removed) new drain hole in the bottom lid (so rusty and thin almost rusted through from the inside in a couple of places!) And I've pushed grease in until squirts out of the new drain hole. No reduction in noise yet but see if improved with some use - once car driving again, soon hopefully! Didn't fancy drilling out rivets etc as described on another post.
Front ones not as easily to add a grease nipple (that does not interfere with the door movement) so just drilled the bottom cap in situ for the moment. Dribble of black iron oxide rich water from passenger side! Spray grease up this new drain hole encouraged some more filthy water out. Again no reduction in noise yet.
I think these check strap mechanisms have the potential to be brilliant, but design let down as accumulates water! (And lacks a drain hole)
If the grease improves things I'll look to weld an M6 nut to each mechanism then the grease nipple will be mounted more sturdily.
Matt