Dear Jagurus,

Here's a merged version of my posts on shocks:
First of all, Thanks for the amazing information! The pouring of help, sympathy, respect, understanding shows great characters here. The 'jag gurus' or rather, Jagurus, are once again sollicited. Thank you all.

I decided to ride the car and pay particular attention to suspension and noise. Not only I'm really getting more and more scared on how the 2004 xkr handles but today at maybe 35mph, the car bottom (under) touched the road as I was driving. Granted it was a dip on the road, never had I experienced a car touching under, other than when going on and out of a strip mall parking and such.
The car literally touched the road while riding the dip on the 'down rebound' if that makes sense.
It was a long dip, maybe one foot of depth by 9 feet long and wide enough for both wheels. When you enter a long dip, the car first feels light, then rebounds down. That's when it touched. So obviously, looks like shocks didn't support the car at all and let the body get lower to the point of touching the asphalt.
I'm not getting any light or message saying the cats or the shocks have problems. Plus I've read in this forum that cats managed shocks rarely fails.
So I've been wondering could these foam parts that you mentioned about could cause such a poor support of the car on bumps and dips? Could this be bushings? Could it make such a difference to replace these foams that it'd feel like having new shocks? The only thing I see without unmounting anything (I'm not really good at mechanic) is the shocks mounts have on top, the rubber part rotten. I suspect the shocks to be shot, but dropping that much on a road light dip, that was weird. If it had been 1 or even 3 feet wide I kinda could understand, but on 9~10 ft, the drop should be gradual enough to be absorbed by the shocks no?

So I guess the info I'm looking is:
1/ can foam or bushing be so bad that it would be like having shot shocks?
2/ do cats managed shocks fail, and due to the car being low (20" rim though) , can car's front 'belly' touch the asphalt (at rebound) while driving.
3/ can bad mount seriously affect suspension/shock primarily function?
4/ would cats system warn through console messages or obd2 codes that shocks are leaking or failing?
5/ if I decided to replace all shocks and mounts with non electronic adaptive, do you need to plug the disconnected cats wires so they don't just dingle under the hood?
6/ I fear for the small cooler radiator that can be seen from under the car, the one that sticks out a bit lower the chassis (Oil cooler?) that it could hit the asphalt too.

I know this is a lot and I apologize for the long message. I'm just so frustrated, so bummed by how the car drives and feels unsafe when going above 20mph. She's beautiful, and I'm obsessed with her, but I don't know what to do besides going to a garage and pay thousands to get this fixed.
Thank you so much in advance for your input.
If one of you know an honest mechanic in Los Angeles that can help with that please let me know.

Thank you so much. Cheers friends

Right side. It's a shadow not a stain like on the left side...


left side. Looks like oil leaked huh? Look at the top left corner , WTF is that? That's not part of the strut...

This one (Right side) has a shadow but nothing on the strut like the other side

Left side,looks like some oil, or dirt? On the shock/strut

This one looks like there's a leak. Notice the top left corner. Looks like a leak too...I don't think it's the shadow

 

Alexanderthegreat,

Chill! You're not alone, and it certainly seems to be the season where many are refreshing their X100 suspension. I just did mine.

Hard to tell from the photo if your shock is leaking. You'll need to get the rubber crocodile gasket off to run your finger along the strut. Best sign - Is the car "bouncing" excessively when you hit a road bump?

(quote) Question - "So I've been wondering could these foam parts that you mentioned about could cause such a poor support of the car on bumps and dips? Could this be bushings? Could it make such a difference to replace these foams that it'd feel like having new shocks? The only thing I see without unmounting anything (I'm not really good at mechanic) is the shocks mounts have on top, the rubber part rotten."

First thing is that, yes, bad strut mounts and bushings (combined) seriously affects the car's ride. The top strut mount is integral to the car's ride height and Forum members use words like "It's pan-caked" ie it crumbled to a flat disc where you say you see (quote) ".... rubber part rotten." Also the bottom shock damper bush can fail leading to lost height too. Check out threads below where there are some pictures of bad suspension.
https://www.jaguarforums.com/forum/x...oo-low-215024/
https://www.jaguarforums.com/forum/x...ension-219489/

An easy thing to measure is the ride height. See table below. It's measured from the centre of the wheel to the top of the body's wheel arch. That'll let you know if you have trouble.


Your low front end height may also be due to long term sag of the springs. Note that generally shock dampers manage "rebound" for the return so you don't get "bouncing." I can't really comment on your questions on the Jaguar CAT active suspension system as I don't have it. However, in order of priority, I would look at 1. Upper strut mounts 2. Lower shock bush 3. Springs

If you're looking for parts, see the recent thread below about where to find parts
https://www.jaguarforums.com/forum/x...ebuild-221544/
But technology has come a long way, and combined coil over (combined spring and damper) units are now available. You have a lot of options if you're moving away from the Jag set up.

Some temporary fixes include putting a HDPE/PU spacer on the spring to make up lost height. It's all DIY-able too if you don't mind getting the wrenches out, and any professional garage should be able to do the work.

Good luck

 

that doesnt look like a leak to me but maybe wheel cleaner sprayed through the wheels and or tire dressing

 

I just finished installing an all new front suspension yesterday....I had the adaptive suspension and YES...the shocks are extremely expensive...SO...I went without the adaptive suspension shocks...$45 each....I replaced the springs with nice Eibach Sport Springs (actually had to buy a set front and rear) and Poly Bushings all around. New everything really....ball joints, tie rod ends, rotors, brake pads, etc...etc...and of course the upper shock mounts. All in for about $1000.00. You really don't need the adaptive shocks....they are a nice to have IMO. Car will run and drive fine without them.

 

I am curious where you got $45 shocks? Usually around $100 each for Bilsteins.

 

I don't have CATS on my convertible but just did the entire front suspension set up and bushings, my springs had definitely sagged and i gained almost an inch back fitting new ones, the shock mounts looked ok but replacing them with Poly also gave me more height and a much better ride, I replaced the shocks to be on the safe side but I think they were probably ok. Bump stops were both missing as well. The control arms top and bottom seem to allow a lot of movement and they were all replaced with poly bushings. the ride is hugely improved. I have just put new tires all round and after an alignment I am hoping I am good. I scrubbed out my yokohama's in about 3000 miles at the shoulder mostly I think down to the front suspension.

 

Hi David, Jagurus friends,
So I measured the height as follow:
From the center of the wheel to the middle of the body curve (edge of wheel Arch). By that I mean the edge of the arch. In other words, from the center of the wheel until the tape measurer hits the body (going vertically upward). The middle of the arch edge just above the wheel.
Results:
Got barely above 14" front, 16" rear. (Same result on each side)
From the chart I see my problem is front. The missing 1.7' I have, I wonder, could it be just bushings or mounts? Or can it still be the shocks. It's only 1.7" so I'm thinking it could be just that, bushings and mounts, maybe even just mounts. But that's probably wishful thinking... Hehe
I have no idea how much a dead shock would drop in height so...

Let me know what do you think..
Thank you all my Jagurus friends for your ongoing help.

 

I think you may need new front springs along with upper shock mounts and lower bushings. The springs carry weight of the car, not the shocks. I measured about 14.25 inches on both sides before replacing the parts. I replaced mine this spring on my 2000 XKR convertible. Shocks were fine so I did not replace them.

Kevin

 

Really? I thought springs rarely ever failed. Interesting...
Thank you Kevin.

 

+1 to Kim on suggestion of new springs

Yeah you’re way too low on the front end. As a combination of things, upper strut mounts “pan-caked”, lower shock bush, and the “sagging” springs, all would go some way to explain your problems.

Our springs may not fail, ie break, but they will “sag” over time. Just like any mechanical component they get old with use, and their specified height, loaded, will reduce over time. Mechanics call it spring memory but the scientific explanation is metal fatigue where if a metal is exposed to cyclical load over a certain load, the spring compression/extension return will not be the original point.

Never heat a spring as it’ll change it’s material properties. People who cut car springs are just asking for trouble, it changes the spring stiffness, and maybe not immediately but it’ll increase the risk of the spring breaking tremendously.

As I sai, a short term fix is to put in a spring packer/spacer. Hot-Rodders do it all the time to change the height of their rides.

 

Great. Thanks for the advice. I've noticed by reading posts in the forum that very few ever question the shock strut itself. Is that because these rarely fails, being adaptive and all, and suffer less stress than the other components? My first thought was it's got to be the shocks. But from what I read there and there, it's everything else! Hehe.
Thank you for your help, really, thanks.

 

What's the difference between 20-070830 and 20-070816?
In other words, e difference between standard and sport suspension?
And also, how can I tell which one is installed on my car? Does it depend on the wheel/rotors/brakes?

thank you

 

How does the Eibach springs look? Did it lower it the full 20mm?

Any complains so far?

 

Fwiw, very rarely and I mean very, do Bilsteins fail. Also, if your car is a weekend/secondary, consider sending them in to Bilstein and they will rebuild and/or change valving, for a fraction of new cost.
If in California, it's a reasonable adventure, as they are located in the San Diego area (Poway). I've had rebuilds on used Billy's for one BMW, revalving on another set to match NLA specs and a modified and revolved shock for a Lexus model that had no offerings available. In addition, I just picked up a pair of special valved shocks for a '65 Riviera.
Bilsten is a great Company, with an outstanding reputation for quality and service and "Limited Lifetime Warranty in Legalease, but liberal in application. For perspective, my BMW struts run on average $200 ea. Revalving/rebuild used to run $60 ea plus shipping. It's been awhile, so prices most likely have adjusted for the times. Also, if you should call, make sure to pronounce, (Bil- Stine), not (Bil- Steen). The employees take it personal and will correct you on the spot...lol.
Hope this adds value and alternative to decision making.

 

The shocks themselves are most likely ok. However, you should probably replace the shock bushings (bottom of the shock). They need to be pressed in and out though.

 

I might be off on this but I was told that the "R" package is when you have the Brembo brakes and also the larger diameter BBS wheels. There might be other features but I would guess that if you have Brembo brakes then you have the "R" package.