I just picked my car up from the mechanic, who did some work on my lower rear shock stud. I heard an incredible knocking on the drive back and figured something in the upper mount was loose. When I lifted up the trunk panels, I saw that the shock rod was sliding right through the mount.
How is this possible, and what part is missing here? I need to make a quick fix, so I’m very open to ideas. Thanks a million!
Car is a 1996 Volvo 850 GLT wagon. Rear shock is a Bilstein B6.
It doesn't look like there's any part missing. The mechanic loosened the top mount to make it easier to work on the bottom mount, but then forgot to re-tighten it.
You can tighten it with any wrench that fits. If that causes the shaft to spin, you'll have to hold the shaft still with an allen wrench in the hex socket at the top of the shaft.
This nut is supposed to be tightened to a specific torque, but if you don't know the spec or don't have a torque wrench, just make it "gutentite" and let the mechanic tighten it to the correct torque when you can get back to the shop.
It's difficult to tell just from this picture, but it looks like the removable upper part of the shock is missing. This should be fitted over the rod, and have a broad top that would sit on the underside of the metal cup part of the shock, so when the nut is tightened it would all be clamped securely together. If that part were missing, the rod would be free to slide through the mount as in the picture. This would also explain why there appears to be too much thread showing at the top of the shock rod, above the nut.
You may be able to confirm this by looking at the shock from underneath the car. The chrome rod shouldn't be visible there.
If this is the case, there's no quick fix. It'll need to go back to the shop, so they can take it all apart and put it back together properly.
Thank you MTA and Alex Taylor for the answers, as this gave me a good idea of what I was looking at. I was able to take some more photos that explain what happened here and take some time this weekend to replace the shock.
Firstly, I unbolted and lifted up the upper shock mount to see that the washer on the shock rod looked like it had failed rather dramatically.
I was able to slide the busted washer up and down the shock rod, where it was never supposed to reach in the first place.
I had brought my car to a mechanic to get the same weld job done that another Volvo 850 owner had after shearing the lower rear shock stud. When I called the mechanic, they said they didn't touch the upper shock mount. So if they were doing work on the lower rear shock stud, I imagine they levered the eye of the shock off the stud. This would've put force on the upper mount, which I would guess busted the washer onto the shock rod.
I bought a new shock and was able to corroborate that thought this weekend. Ordinarily, as MTA and Alex Taylor pointed out, there's some upper mount—in this case, a washer about half-an-inch thick—that sits at the top of the shock rod and interfaces with the upper shock mount from the photo in my question. That washer shouldn't be able to slide down the rod at all, or else there is nothing keeping the rod from driving up into the trunk panel.
Below is how the shock rod is supposed to look, with the washer and dust cover removed. Notice how the shock rod is slightly thicker than the threaded part of the rod above the split-ring washer.
And this is how the busted rod looked after I removed the upper mount. Notice the damage to the ledge of the shock rod, which is where the washer broke through.
Needless to say, I had to replace the shock and find a new mechanic. Thank you all again for your help here, and let me know if any additional photos would improve this answer.
