Should I be able to turn the upper shock nut (the big gold one) by hand? I have an ‘02 XJR with only 56k on it and it has a clunk going over bumps. I replaced the shocks with factory CATS ones, but this nut seems loose to me, and I can’t seem to tighten it any further. Any ideas?

 

Whoa! Don’t attempt to try any more turning. The nut must be tightened but do you realize that you need to insert an allen wrench down the centre of the shaft to prevent it from turning?

 

I've done that. I've taken them off and put it back on a couple times, so I know it's not cross threaded, and the nut will tighten to the washer, but I can still spin the whole thing. Not sure if that's normal or not. I'm trying the 'easier' things before tearing the suspension apart.

 

I wonder if the nut is bottoming out on the thread? Maybe try a washer or two on top of the large dia one.

 

vice grip on the shaft

 

Pretty sure if you turn that nut on a CATS damper and the shaft turns with it a few times without holding the shaft you'll detroy the internal wire. Need to put a hex socket in the center and tighten the nut.

 

If it's still clunking, it's probably the shock bumper in the mount. It will look OK but they will thrash about when driving and make that clunking sound. I know from experience after changing a lot of parts on my car until I finally changed the mount and years of clunking were eliminated.

 

I know about the internal hex, I've held that to get the external nut as tight as it will go. There is still about 1/4" of threads visible in the nut when it is tight. I can't tell if the shock just won't come up anymore or what. I'm hoping someone with the same car can verify if what is happening in the video I attached with the post is normal or not.

 

See my pic. About 1/8” of thread visible. The whole bushing assembly is tight and cannot be moved like yours. You will note the additional washer. This was not a necessity but just something left over from when I was chasing a suspension rattle. Mine are factory top mounts. Maybe some aftermarket mounts have less thickness in which case the shaft thread could be bottoming out. Something is stopping the bush from being in compression. Maybe do some dimensional checks.

 

It sounds to me like the shock shaft is not high enough in the shock mount, thus the clunking.
What does it look like with the big washer and nut removed? Or is that part of the shock mount?

 

Loosen the bolts on the mount itself. Maybe the shaft is binding somehow. Loosening the bolts should let the mounting plate move around a little bit and maybe let the shock push up through the hole further.

 

Yes!!! I remember I had a slight issue with this on my CATS equipped 2003 a few years back when installing new shocks. Jack up the car a bit to take the pressure off, loosen the top nut, and move the shock shaft around until it moves freely through the mount sleeve. It's a tight fit so it needs to go in just right.

 

Don’t mean to hijack but can anyone confirm the thread direction of the top nut for cats dampers?

Yesterday I was attempting to replace my upper shock bushings, I stripped the internal hex of the shock shaft while trying to turn the nut counterclockwise to loosen. I did the rear bushings and didn’t have any issues with the top nut. I suppose I can try to grab the shaft with vice grips but looks like I’m buying new front shocks if that doesn’t work.

 

Its a conventional thread. You were correct in CCW to undo.
See if you can tap a tighter Allen wrench in there, metric or imperial. Could also try grinding one down for a better fit.
Good luck.

 

Thank you @XJR-100. I was pretty sure it’s standard thread but thought I’d ask.

I did take a 9mm hex and filed it down to about 8.4mm so it just barely fit inside the nut and lightly hammered into the stripped hex but after using an 18” breaker on the nut (ccw) the hex stripped again.

Very frustrating since the shocks are (were) perfectly fine. I used penetrating oil and let it sit for an hour, tried shocking with an impact, and heated the nut with a torch but it’s like the nut and shock are welded together.

Guess I’ll have to cut off and buy new cats shocks. Ouch… so much for an easy Sunday job replacing the top bushings. The rears came apart so easily.

 

Something doesn't sound quite right about the nut not turning.

 

The threaded shaft can’t really be turned much (preferably none at all) because of the internal wires as they’ll twist and break internally. Ask me how I know that.

 

Hi Cookj61,

Compare the nuts that came with your new Bilsteins with the nuts from your old ones. You may find that the original nuts are taller and will thread down farther onto the shock shaft, solving your problem.

I don't know why Bilstein supplies shorter nuts with the new shocks, but I've had the same problem.

Cheers,

Don