Hi everyone. Earlier, I wrote a post where I encountered a very stiff ride after replacing rear upper and lower control Arms. See thread here:
https://www.jaguarforums.com/forum/x...s-help-253049/

The ride has again slowly stiffened up. I replaced the shocks with new Bilsteins 20-441128 and the old ones are pressed down easier and return slower than the replacements but I would not call them shot.
I raised the vehicle to ride height and torqued to specs. Ride is terribly harsh again. I followed PeterV8's advice and loosened everything for a test drive, except the shock lower bolt. No Change.
Then I loosened the lower shock bolt from 98 lb/ft to about 50. Ride improved. It is still not great but appears to be the problem? It's that binding feeling I noted in my last post. FWIW the CATS is fully operational.
Next step will be to tighten the control arms back to spec, leave the lower shock bolt @ 50 and take another test drive.

Question for the many minds brighter than mine assuming I still get failure: Noting the lower shock slid in place smoothly on install and all parts are relatively new now, is it possible that the lower arm needs a wee bit more room? Perhaps take an angle grinder and shave off 1/16 - 1/8 of an inch off the arm @ the lower shock and then re-torque? Stupid idea?

Or replace the lower arms? I replaced the lower arms from OEM to Mevotechs and then with Moog. Money is now a concern. I could replace with Eurospare $266 for the pair.

I've been repairing cars for the better part of 50 years and the system is just a standard double wishbone. Dazed and Confused was a great movie but not a great feeling.

 

If you need more room, you ought to be able to see wear on the hardware where the impingement occurs. If the problem is friction between the shock and lower arm, to me, it points to the bush being too short in the shock rather than the control arm being too tight, especially since you've tried 2 different manufacturers already. I also used Mevotech arms when I rebuilt my rear suspension, and it stiffened up considerably. I never drove one of these when they were brand new, so I have just assumed that the stuff ride is correct. (I also nearly always drive in S). I continue to follow your saga with interest.

Is it possible that the bush is being compressed to the point that it bulges in the sleeve, adding to the friction? Spitballing here.

 

Shocks are brand new Bilstein's and the bushes have a metal center sleeve that the bolt slides through so the bolt snugs up metal to metal - no bulging of the rubber. The OEM shock (I assume original is the same and the symptoms were the same before swapping out the shocks. This is true with the bush at the wheel hub too. Using a jack, movement feels and looks proper though what you say makes sense. The metal in the bush should not move if I understand their function correctly. The rubber should flex with up and down movement while the metal to metal doesn't move? Do I have that right? If I do, then why would the ride soften (a little) when the bolt is loosened?

 

I'll also ask as I already feel foolish. Are the top shock mounts directional? Often with the top mount there is an arrow that should point out to the fender or on some cars, the front but those type of mounts are angled. I didn't see on and once the springs are fitted, they appeared to be straight (no angle) implying to me that the four top mount bolts can go into any hole. I did use paint on one bolt (okay my wife nail polish) and put them back the same orientation. There is no resistance at the lower Bush ie I don't have to struggle to align it.

 

Also interested in the above question. Are they? Thanks.

 

I have never seen anything indicating that shocks are directional, and they both have the same part#, so I'm going to go out on a limb and say they are not directional.

But if you sandwich a cylinder between 2 flat plates, eventually even metal will compress and bulge. If that happened in this application, it could increase friction on the bearing portion of that joint. Which leads me to think that the aftermarket arms could actually be a slightly different hardness - So the higher torque bends the tabs at the bolt holes, allowing the cylinder in the bush to slightly compress. (I am speculating here, I don't have any actual evidence of this. I throw it out for argument purposes only.) Could be that the OE arms are harder metal.

 

Thank you @007XKR . I did pull the drivers side shock again. Disassembled and reassembled, then stood it upside down on the four mount bolts an it's straight up and down (sorry, no pic). Not angled though.
The four mount bolts are not equally distance from each other (slightly rectangular) so you can mount it, dismount and rotate 90 degrees and the stance is the same.

What I am seeing is that once the top is cinched up, the lower end of the shock at the bush mount point is about an inch outward and I have to push it in and hold it there to get the lower bolt in. Perhaps this is the issue and I'll post a video tomorrow of what is happening. For those that have installed the rears, did you encounter the same?

 

Sean, since the four bolts are somewhat of a rectangle did you try flipping it around 180° and seeing where the bottom of the shock pointed in that case? Did it point to the same place in both positions, or did you find there was a difference?

 

Hey @panthera999 yes. I mean't to say 180, not 90 but I did flip it. Just got back from a test drive. No difference but working on uploading the video.

 

 

It also doesn't align with the top bolts loosened

 

Hey Sean - I’ve done my fronts a couple times and the alignment when putting it back together is always a PITA. I think it’s due to the geometry of the components at that point. The shocks are uncompressed, and the rest of the suspension is hanging lower than normal as you try to align the holes. If you were driving, and went airborne to get the suspension in this position, the components would probably be stressed too, as this is not the position that they should be in when normally weighted down by the vehicle.

 

Maybe a dim question from me, and I haven't checked the service manual, but on many cars, the suspension should only be tightened up with the weight of the car on the wheels/suspension. Is this the same on our cars?

 

Not a dim question @neilr and yes, the manual says tighten all to spec while on it's wheels.

 

If my memory serves, I did have to manipulate the shock and control arm a bit (up & down) to get the bolt in, but it seems like it lined up correctly on the control arm receiver.

I've slept a few time since I did it, so my memory could be fuzzy.

 

@panthera999 I did another 180 with that shock and it no longer leans forward so it's my assumption the isolator position affected that. Slides into place now. Still no joy on the ride but I'd advise anyone to mark one top bolt with paint so you position correctly.

On to the next issue. My isolators are crap. Started shopping around could only find one on eBay. Reached out to Palm Beach Jaguar. Per the electronic parts catalog, part # = C2P3210 which was superseded with C2D16903. $115 per isolator. Yikes. He also mentioned that you can't buy the top hat (top mount) from Jaguar as they only sell the entire shock. Well ok then. I don't need the top hat anyway. I measured the mounts on the front and they are the same bolt configuration. When I dropped the shock, I read the isolator part number.
Part# 6W83-30357-BA but that seems to bring up tweeters. I'll update when they come in. You can also buy the whole set C2D51875 on eBay which states it's for front end and fits multiple cars, including ours though it stated for the front end. Dug a little deeper and found a German based part supplier that lists them all as interchangeable, front and rear.

So I've ordered the Eurospare lower arms (I surrender) and will order the isolators as well.



Pic after rotating back to OEM position - no more forward lean.

 

You can use a spare trolley jack to support the knuckle without having to use a wheel to assist with tightening the suspension bolts.

 

Yep, thanks. That's what I do usually. I just raise it until it starts to come up off the lift. I also have a pair of 12" wheel cribs but don't use them often.

 

Eurospare arms installed. Problem is no more. Makes sense as the problem began when I replaced the OEM arms, first with Mevotek and then Moog. I have my ride back but going to replace the isolators this weekend. Thank you to everyone for your input. Much appreciated. @GGG please mark this thread resolved.

 

That’s great news. So what’s different about those other arms that caused the stiffer ride?