So I have a 97 XK8 convertible that has front suspension sag. Vin 017562
100k miles 160 Kilometers.
Clearance is 14.25 at the front wheel arch, too low?.
Travelling down a B grade road, I hit a large pot hole and the noise of the shock compression hitting the mount, got my undivided attention.
Time for a complete rebuild?
At least it is a non CAT version

I have splashed out and purchased genuine shock mounts, 600 AUD each. Around $420 USD, ouch, along with other required components,
Discussion on the Forum was not all positive about the quality and longevity of after market products so I elected to go with the original components.
In a prior thread someone was exploring the OEM v After Market Shock mount components as a comparison for longevity and other aspect., I could offer up my experience at a latter date for some qualified and quantified data on the "Top Mount "saga.

Given that I live Down under shipping and exchange rate AUD v USD adds around 40% to the bill, plus Tax 10%, cheaper for me to go OEM and local dealer being a bit flexible on price..

My problem is identifying the correct Spring as part of the rebuild if required.
Research has shown that the coupe 97 XK8 models have different shock spring rates than a convertible and XKR.
My understanding is 97 convertible and XKR same spring rate.
Later models are different in coil size, free length, spring rate, apparently. USA market springs, UK market springs etc. All a bit confusing as shown in prior threads.

What about free Spring length?
I see info saying from 370mm to 400mm or 16 inch.

My objective is to have the car ride height around standard settings say 15.75 inches.
I can get a pair of used XK8 convertible Springs that measure 370mm P.No JLM 20706

Does anyone have the correct OEM Spring specs for an early model 97 XK8 Convertible, please?

 

l would be doing just mounts first off, you may well find all the ride height loss was in those alone.
Just as a matter of interest l could have supplied improved design replacement spring pads and shock mount bushes in poly, l am also "down here" in oz.

 

I have the same problem 14.5in and have just bought some new springs in UK for £55 the pair . They are exactly 400mm high and for a 97 Coupe
Too cold to work now but intend to pour poly if necessary and or fit spacers made from cutting board.

 

Well, it must be spring time! Today I've started replacing the front springs on my 98 XK8 Convertible. I too live in Australia and bought my Suplex German made springs through Berkshire Jaguar in the UK. I agree that postage is a killer, but my springs arrived less than a week after ordering. They will confirm which springs are appropriate for your VIN.

I was experiencing a 14.5 inch measurement at the front and that was after replacing the shock mounts and all bushes and ball joints. After scraping the front a few times on pavement crossovers, I decided the springs needed updating.

My new springs are 400mm, some 40mm

New and old spring comparison
longer than my old springs when relaxed. Hopefully this will give me my 15 inches plus, for a few years at least. The attached photo shows the new and old springs.

 

It seems there is a common aspect here in respect of the clearance.
That is, sometimes doing just the shock mounts doesn't rectify100% the wheel to arch clearance, as you initially found when doing the mounts etc, minus the springs.
I replaced the front Bumper undertray, and it is very disconcerting listening to your $1500 AUD piece of plastic collect more gravel rash as it goes over driveways and anything else that sits above ground level.
I feel that as everything is out I may as well replace the springs and all the other rubbers, although they look fine and no movement, it will save the grief of having to do the job twice.
Your new spring measurement of 400mm or 16 inches confirms the correct spring length as discussed in prior posts.
Now all I need to confirm is correct spring rate for the early vin XK8.
Thanks for the pics shows the difference clearly.

 

My undertray suffered badly too but my budget so soon after buying the car didn't run to a replacement. I invested instead in a hot stapler, some sheet plastic and filler. It's not perfect, but perfectly useable.

Before

After repair

 

Nice job, I couldn't repair mine as I only had one side.
Looking forward to reading the results when you finish the suspension job, and have done a few miles, especially the clearance measurement.

 

The results are in... When I lowered the csr onto its wheels it was measuring a massive 16.5 inches but I knew that would come down with the first drive. After a 20 km drive I have an even 15.5 inches, which is about an inch better and just about on spec.
While changing them over I noticed that one side had no rubber spring assister and the other side produced this sorry looking piece of rubber.


Remember to order a couple when you get your springs.

 

Great outcome, Redjags.
You certainly knocked that job over quick time.
This Old Bloke is going to do it over a couple of weekends, along with the speakers, but that's another story. I have the Bump stops.
The extra 40mm or 1.5 inches over the old spring produced a good result in regards to clearance. I hope it was a noticeable difference on the road?
I did a calculation Old v New springs and as you are now at 15.5 inches it raises two more questions.
Have you replaced the Spring pads as part of the job?
And the answer to a question I am seeking, Do you know what the spring rate is?

 

I reused the bottom spring supports and seats as they were in good condition. I'm not sure of the spring rate but the springs are rated as OE, which I assume meets the original specifications. They, and the new shock mountings and bushes have got my car back to its original height. Handling is now so much better than my original test drive. Now to get balancing and alignment checked and it should be like new. It's good to see that the car is now sitting as it should.

 

I will have to do mine at some point but I am looking at the Swallows coilover kit, it's a lot cheaper then the CATS shocks and springs but should be better everywhere. I'm at 14.5" at the front as well and get a knocking on the left hand side of the car when driving on unever ground. My mechanic says the bushes are all OK so I would think it's the top mount, it's red but not crumbling yet. I get squeaking as well sometimes. I need to get the rust sorted as well and I want to get her on my 18" wheels I have in the garage.

 

Due to the varying info available regards Front Springs Specifically for 97 XK8 Convertible, I took the plunge and ordered 2 springs from Berkshire Jag Components half way around the world.
When they arrived as per usual I measured the Length of the springs, expecting them to be the 400mm length. To my concern they only measured 380mm in Length. The old removed springs measured 375mm. I sent Kelly at BJC an email explaining my concerns re the shorter length.
Kelly investigated the situation with KYB and the following is an excerpt from Kelly's email.

We currently have 400mm in stock of the Supplex brand. The ones you have there should be the KYB 380mm. KYB have fully intergraded to the Jaguar specification.

Supplex are phasing the 400mm out and gradually changing their springs to the correct specification as Jaguar.

If I was to purchase these from Jaguar today these will come in at 380mm under the new specification.

You will find 400mm is in circulation as there is nothing wrong with a 400mm as long as they use the correct thickness coil for the 400mm and the correct thickness for the 380mm then they will both have the same end result.

These would be for the Convertible Jaguar as the Coupe are a different style due to the weight of the car. when speaking to our account manager he has checked them under the number we purchase these as. I am trying to get the spec of all this information as we are updating our website with new product details and this always comes in handy.

There were several emails but Kelly got to the bottom of the issue and we now have further knowledge on the subject of springs.
Additionally info was provided that from 98 on the KYB spring is the correct replacement for the earlier model convertible.
Thanks Kelly at Berkshire Jaguar Components.

We all learnt from this experience and hopefully when everything comes together I will have achieved the correct ride height,

I still haven't had one question answered, and that is what is the differential of the Spring Rates of the 380 v 400 Springs?


The spring on the right is 380 as well just not lined up properly.

 

I have some 400mm springs waiting to be fitted to my Coupe. I expect them to be higher than the specification initially and then to sag to the right height , The spec shows a "showroom height" greater than a run in height . We shall see.

 

a 1/2” to one inch spring spring length drop / reduction after 0 to 200 miles is typical of all new aftermarket automotive springs, not just Jaguars.

Z

 

The shock replacement is done.
Baxter's top Strut mount assembly upgrade, new Bilstein B4 shocks, these came complete with new bottom bushes, new bump stops and the KYB springs.
FYI the KYB springs do require good quality spring compressors. These are HD springs. Ask me how I know, close shave.
We didn't have to remove any suspension components except the roll bar top links.
The 97 XK8 on the RHS rear wheel well, has a small bracket held by a couple of bolts when removed slips back 50mm or a couple of inches and allows plenty of room to slip the shock into place. Same with removal.
LHS, a bit of messing about getting the bottom mount in, but still easy.
You will have to put some downward leverage on the lower control arm to give it the little amount required to slip the bottom of the shock into place. Required on both sides.
After not finding out the spring loads of the new springs I just got onto the job.
The end result is, after around 50miles (80 kilometers) on B grade roads, the car sits with a +15.75 inch clearance, exactly what I was after.
The ride quality has improved so much, being firm yet compliant, and coming up the driveway no scraping.
Objective achieved and a little knowledge gained along the way.

 

Well done....