I recently replaced the rear upper and lower control arms, stabilizer links and toe link, also the front outer tie rods and upper control arms.

When finished, and I lowered the car, the ride height was way too high so I drove it around a bit and it lowered. I drove it for a day but not too much as I needed an alignment.

Next day when driving to the shop for an alignment, I noticed the ride was stiff - like the dampers were stuck in firm mode. It still is.

No CATS faults, ran a quick DTC check with IDS and no suspension codes appeared.

Ride height is 15" in front and 15.25 in the rear measuring from the center line of the wheel to the top of the arch.

I can't help but think I did something wrong reinstalling the height sensors but the height is correct (I did this with the gas on 1/4 tank. I will fill and recheck the ride height.

CATS fuse is good as well. (Fuse 14 in the drivers side footwell)

Any ideas would be appreciated. Am I missing something?

 

Did you support the suspension to proper ride height prior to final torque of the bolts? If not you may have tightened the arm bushings in the wrong positions. Also have you tried removing the CATS fuse to see if the ride gets any stiffer?

 

Good thoughts Jahummer, thanks. I pulled the fuse to test it but didn't drive so I'll try that. I used a jack to lift the wheel hub under the lower arms to tighten in the rear. The front uppers have been fine as I was driving with them for awhile before I started having problems. I can't get under the car with a wrench when it's on the ground for the rears. It's possible I had it lifted too high?

Edit. I just measured the pitch of the lower control arms with the car with on the ground using my protractor and they sit @ 4 degrees. I'll put it back on the lift and raise the hub to the same height and re-torque the upper and lower arms. But I'll pull the fuse first and drive it to see if it gets even stiffer.

 

Jahummer, thanks again, re-torquing everything solved the issue. I drove it to the gas station afterward and fueled up, then pulled the CATS fuse for the drive home. Very firm ride. I dragged my wife along for another drive and she said it rides normal again.

Just for grins, how does everyone get their car to the proper ride height? I used a protector as I mentioned, but would it also be acceptable to just lift the control arm under the ball joint to get to the correct ride height measured from the center line to the top of the arch? For my car that's 396mm +/- 15mm.

Thanks again!

 

Sean, glad I was able to help and all's sorted, didn't realise this is not common knowledge when replacing suspension components. When the car's in the air and the suspension's no longer supporting the vehicle weight, the geometry changes entirely. Therefore it's necessary to support the knuckles only and raise them to standard spec height, usually measure from the centre of the hub to the edge of the wheel well arch while the car is on the ground. If this procedure's not done properly and the suspension's torqued to spec in this position, once back on the ground and settled, the geometry will be completely off and the positions of the suspension bits will be all off resulting in damage to the suspension, bushing, poor ride quality and difficult if not impossible alignment.

 

It probably is common knowledge and I was just dim. I lifted the knuckle too high originally. Not happy with myself but it's good now.

 

I took a few trips recently and it felt like my ride was to firm again. Wife and I drove around this morning and she said the same thing. "I feel every bump".
No codes thrown. Fuse is good and while there may be a change in firmness when I pull the fuse, it's not too different. Here's my question as there is no reason for this change imo without a CATS failure of some sort (which would throw a code). I was re-reading the workshop manual and came across something I'd like to run by you all

Rear Torque Specs from the manual -


Note the lower arm to subframe Torque spec says 121 lb-ft to subframe and spec to hub is 110 lb-ft. And yes this is a snapshot of the rear specs.


Now further down in the R&R section I see this:


OK so the hub is still 110 lb-ft but the arm to subframe is stated here @ 72 lb-ft. Typo at one location and I would think 110 is correct but also wondering if this is stiffening the ride.

In retrospect from my previous comments, I don't think it was ever smoothed out as prior to changing the control arms, just improved once adjusted from the correct wheel height. I looked at all of the other rear suspension specs and compared them to their respective R&R sections and they all match up, except the one I noted.

What's my risk here if I adjust the torque down to 72 foot pounds and it in fact smooths the ride out? I should see no change in the rear toe by loosening it correct? Honestly, I'm not sure what else to try. Rear has all new parts and IDK what I could be doing wrong.

Also FWIW I took a look at the 2010 onward and it's bizarre as well. Here are the specs (samsies)



But look at the R&R spec


So here it's 192 Nm which is 142 lb-ft not 121

The problem is most likely me - Apologies for the long winded post. The real question is in Bold but any other input is appreciated.

 

I may have finally resolved this a few days ago. I put the car on the lift and was doing a visual inspection. I noticed on both sides of the vehicle that the two rearward lower arm bolt ends were in contact with the subframe, as though the bolts were about 1/8" too long. I pulled them both and compared them to the OEM which manual says to discard. They are exactly the same length.

There was some paint removed on the subframe where the bolts ended so they were rubbing against the subframe. Bolts slid right out and aren't under any twist tension.

The lower arms went on smooth and easy when I initially installed them and yet I somehow turned this basic grunt work into a senior science project.

Well screw it. Don't care why anymore. I added a couple of flat washers in front of the bolt head, put some anti seize on the non threaded part of the bolt and torqued to 110 ft lbs.

Car is currently riding smooth as glass. Will see if it holds up and maybe I'll get a ribbon at the next science fair. Wife says if I take a picture, she'll put it up on the fridge right next to the grandson's drawings.

I still don't get the discrepancies in the manual but I'm gonna call it done.

 

Maybe not enough clearance to do it, but could the bolts be in backwards?

 

Correct Ken. Not enough clearance. They only go in one way

 

Hey guys,

Thought I'd tag onto this thread here about suspension etc. I replaced almost all my suspension parts recently (UCAs, LCAs, tie rods, shocks) and found another thread on here about that very helpful. After I replaced most of those parts, I got a CATS error on the dashboard. I've been trying to figure out the problem for months now and have taken it to several people, shops etc. to figure it out. Finally took it to a local independent Jaguar shop in LA and they ran a diagnostic for $125. It came up with this:

C110F-14 R/R Damper Solenoid Short Circuit
C110F-1D R/R Damper Out of Range

My question is, why wouldn't that shop be able to tell me, after their diagnostic, that they isolated the problem to the shock itself? Can't they test the wiring harness that goes to that shock to make sure it's functioning well? Volt meter or something? Or is $125 charged just to plug in an OMB2 reader (an enhanced one with additional Jaguar software or data capabilities) and any other troubleshooting is billable as extra. After going thru months of this CATS failure error, I finally decided to just grab the old shock which for some reason I'd kept, and plug the two pronged sensor cap into it. Voila, CATS error gone. This led me to believe, as I'd previously been told, that some new parts come out of the box failing like that. I contacted Rock Auto and am having a new shock sent out under warranty. Of course I have to pay for new shipping and the additional labor of getting to that recently installed shock and putting in the brand new one. Not an easy OR CHEAP job either.

I can guarantee you, next time I put a part in, I'm gonna connect electronics to it before the full install, that could have saved me some of this grief.