I recently had my 940 drivers door detent spring snap.
Volvo hinge 9244768 NLA. 700/900 /V90/S90
I found a used hinge in good condition and replaced.
It had some wear on the detent spring and the shoulder studs that hold the two detent cams.
My Volvo trained tech friend had greased the hinge cams for me,
but now I see there's more to servicing those old hinge detents.
The detent cams can freeze up. You'll get a clue if you hear a snapping
noise when opening the door. If the cams are free and greased they're quiet.
Once the cams bind up, they start cutting through the spring.
when the wear gets severe the shoulder rivets holding the detent cams also
start cutting a groove in the spring just above the detent groove.
I was surprised to find that my spring did not snap at the wear groove at all
but at the very top of the spring.
There's what looks like a short stainless sleeve at the back of the spring
up top where its staked into a groove in the hinge bracket. It looks like
mine had seized up there helping the spring to snap since it could not twist
over it's full length. Some mystery oil and working it back and forth had it
free as a bird in seconds.
So there's another spot that needs mystery oil followed by a drop of machine oil.

www.swedishcarparts.com sells a hinge spring #1355200-S for 200 series but they
dont know if it will work with 700/900. It looks like the same spring to me.
Has anyone used this spring in the 700/900?

https://swedishcarparts.com/parts/search?utf8=%E2%9C%93&search_text=1355200-s

They say that they have the spring made in the USA and that they sell a lot of them.
I haven't run across any posts about that, so maybe it's some dealers using them?

I've got my old hinge and trying to get the cams free, They have been soaking in MMO and freeing them up in the car seems a problem. One of the shoulder rivets for the cams is loose where it's staked into the hinge bracket. Dunno if it can be tightened up OK with a BFH and a cold chisel or not.

The shoulder rivets must wear from the hardened detent cams. So rebuilding a hinge may require new shoulder studs. For someone with a machine shop it would be easy to make new hard/ SS shoulder screws that could be installed with a SS keeper nut. Maybe not if the keeper nut has a larger OD than the shoulder rivet,
you need clearance to the detent spring.

Phil? Maybe you know someone?

The takeaway from the above is that if you are hearing clicks and snaps, and in Phil's case, if his wife is hearing clicks and snaps when he opens the drivers door, (or any door) it's time to clean and free the detent cams and get mystery oil into the cams & spring sleeve until the noise is gone. Then put the grease to the detents, and a drop of oil on the detent spring sleeve.
Then you'll get more mileage out of that geriatric spring.
This beats replacing the hinge, which is a pain you know where.

Happy motoring, Bill