XJ6 & XJ12 Series I, II & III 1968-1992
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XJ6 1978 S2 ride heigh problem

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Old 06-16-2018, 03:41 AM
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Default XJ6 1978 S2 ride heigh problem


Hi I’ve rebuilt the suspensions on the car, new springs, shocks, rubbers etc front and back
With the axles off the car.
Now that they are back on the ride height is way out, the front is over 2” higher than it should be but I can’t see what I have done wrong?

hopefully the pictures show the problem and someone can tell me what I’ve done wrong.
thanks

Graham




 
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Old 06-16-2018, 06:07 AM
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Jaguar used packers under the front springs to "adjust" the ride height.

Messy, hell yes, and time consuming.

Add to that equation, that "new" springs are usually bit exactly the same as the OE of the 1970's.

ALL the blah, blah, blah about them made to OE spec etc is not always fact.

I have nothing but issues with "new" springs over the years, and usually ended up at a wreckers (breakers) and hunted down a pair from another car, and fitted, and the whole thing simply fell into spec.

We dont have much issues with springs down here, but clearly, from what I have read over the years, you guys do, salt etc I suppose?

If you have fitted the packers, some need to come out, and I have long forgotten the formula that applies to packer thickness versus ride height variation.
 
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Old 06-16-2018, 06:36 AM
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Some years ago my series 1 was really sagged at the front, so much so that the car only looked right with both tanks full and another 100lbs in the boot. So I bought some springs from a suspension place that were supposed to restore to the correct height. They also had on offer stiffer springs that would increase height 25mm. Put the standard springs in and ride height was 585mm at the lights. Took them off, returned them for the stiffer springs. Car rides at 622mm (R) and 626mm (L), still a bit high but better than scraping on the kerbs. So I assume your springs are way too stiff.
Grant - can you just confirm that adding a shim (they are 3mm plastic) will INCREASE the ride height (I think it is 8mm) and vice versa?
 
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Old 06-16-2018, 07:25 AM
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Drive it for a few days. Give it a chance to settle. Then if the springs feel ok and they arent v12 springs add spacers and longer bolts to the lower spring plates to achive the ride height you need.
.
 
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Old 06-16-2018, 07:27 AM
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Originally Posted by Grant Francis


ALL the blah, blah, blah about them made to OE spec etc is not always fact.
Yeah, when you see a listing showing a single part part number for a spring that Jaguar used 5 or 6 different variations of, you know something ain't right !

Over the years I've determined that getting correct ride height with new springs is maybe a 50-50 proposition at best.


I have nothing but issues with "new" springs over the years, and usually ended up at a wreckers (breakers) and hunted down a pair from another car, and fitted, and the whole thing simply fell into spec.

I did the same on my latest project


If you have fitted the packers, some need to come out, and I have long forgotten the formula that applies to packer thickness versus ride height variation.
It's roughly a 3:1 ratio. One .125" spacer yields a .375" difference in ride height.

I'm not sure spacers/packers will account for a full 2" height problem. They're designed for 'trim'/adjustment, not compensating for gross deviations.

Cheers
DD
 
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Old 06-16-2018, 07:31 AM
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Originally Posted by icsamerica
Drive it for a few days. Give it a chance to settle. Then if the springs feel ok and they arent v12 springs add spacers and longer bolts to the lower spring plates to achive the ride height you need.
.

Yeah, sometimes they do settle a bit.

I also wonder if the springs are fully seated at both ends....although the way the seats are designed they really should sort of guide themselves properly home.

Cheers
DD
 
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Old 06-16-2018, 07:46 AM
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I agree Doug, and not a 5 minute task to R & R springs as a trial and error thing.

That spring makers "one size fits most" is getting way too common.

Probably V12 springs at a pinch.

Doug has answered the formula and its sound sort of familiar, its been a very long time since I messed with them.
 

Last edited by Grant Francis; 06-16-2018 at 08:16 PM.
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Old 06-16-2018, 09:00 AM
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Originally Posted by Grant Francis

That spring makers "one size fits most" is getting way too common.

Probably V12 springs at a pinch.

Yeah, I agree.

When there's a problem the complaint always seems to be "too high" rather than "too low". So I'd guess that the spring makers, in their one-size-fits-most approach, are making the springs taller and stiffer to accommodate V12s.

Cheers
DD
 
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Old 06-16-2018, 01:52 PM
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Wrong springs or badly made ones ! I had to replace a set way back in the early 90s because they have a tendency to break about an inch off the bottom end and this is a failure on our UK roadworthiness test (MOT Test). My car did ride a bit higher afterwards, but eventually settled down a bit,but a 2" difference is obviously wrong, way out wrong.
 
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Old 06-16-2018, 02:06 PM
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Default Ride height

thanks guys, it’s good to know I haven’t done anything obviously stupid, I put the shims under the new springs exactly as they came out so the set up was the same but I guess I could have allowed for the new springs being stiffer, either way 1/8 th inch or so wouldn’t make that much difference.

going to see if it passes an MOT soon for the first time since 2004 and then onto stripping the interior out and getting it ready for a respray.



 
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Old 06-16-2018, 03:32 PM
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Just lowered my S1 about two inches with 1/2 inch spacers between the pan. Headlights will be WAY out of useful height!
 
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Old 06-16-2018, 03:50 PM
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Default Suspension

Originally Posted by Fingers13

Hi I’ve rebuilt the suspensions on the car, new springs, shocks, rubbers etc front and back
With the axles off the car.
Now that they are back on the ride height is way out, the front is over 2” higher than it should be but I can’t see what I have done wrong?

hopefully the pictures show the problem and someone can tell me what I’ve done wrong.
thanks

Graham




Graham
Measured mine today, never did any changes to my car since 78.
The front is 27 3/4, the rear is 24 1/2 .

I think my rear could use a boost, I have a set for the rear to be put in.

Walter
 
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Old 06-17-2018, 02:56 AM
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Default Ride height

Thanks Walter, I take it the 27 3/4 inches was the wing measurement not the light measurement which would be about where I need to get too.

Roger what did you remove to lower you S1 by 2” I have 1 shim top and bottom from memory which is the only adjustment I can see.

The springs came from either British Parts or Barratts so I‘ll dig out the receipt and follow up with them.

I took it out yesterday for it’s first run and it does fee very stiff.

Graham
 
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Old 06-17-2018, 05:09 AM
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I put the original V12 springs back in and with a lighter 350 Chev it still is not as high as yours. There was a 50mm diff in height in the 2 different sets of springs and that 50mm turned into a 110mm difference on the car.
 
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Old 06-17-2018, 06:44 AM
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Gentlemen, I have been following your discussion with great interest as my 1979 S3 sits too high. But a more basic question is what is the correct height and how do you measure it? I have seen comments about measuring to the center of the headlights but the bumper sticks out so far the measuring tape is a long way from the headlight. Is there a definitive target measurement to the top of the front wing (fender) wheel arch? Are S1, S2, and S3 all the same? Sorry to hold up your discussion with such a basic question but I think a lot of us are looking for help on this. Thanks
 
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Old 06-17-2018, 08:09 AM
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Although both front springs were broken they were exactly the same height as the new ones I put in.

let me see what the supplier had to say, they are both reptutable companies in the UK

my book says 611mm minimum to the centre of the lights.
 
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Old 06-17-2018, 09:54 AM
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Perfect. Thank you very much for posting this page. I am going to print it out and put it in my Jaguar book. Thanks again!
 
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Old 06-17-2018, 10:17 AM
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I'll add that my Series III ROM shows the same spec....611mm

Cheers
DD
 
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Old 06-18-2018, 07:29 AM
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I had no packing rings in my S1, did not want to try replacing the springs.. too many others had higher than normal results by changing them out.. King springs seem to be made out of spec?

So I added (tried 1/4" spacers first) 1/2 steel spacers and used 1/2 longer Grade 8 bolts, washers and nuts. There are two sizes, longer ones in the front that hold the shock mounts and the shorter ones on the sides. I just loosened the front ones and the ones on one side, then removed a side one to gain the needed room for the spacer.. replaced that bolt and then did the rest on that side.. repeated for the other side.

One photo shows the half inch spacers installed. the other the results with only 1/4 inch spacers. Car is now at correct height and I then adjusted the headlights to aim properly!!!
 
Attached Thumbnails XJ6 1978 S2 ride heigh problem-quarter-inch-spacers.jpg   XJ6 1978 S2 ride heigh problem-half-inch-spacers.jpg  
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Old 04-13-2019, 10:08 PM
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Originally Posted by Roger Mabry
I had no packing rings in my S1, did not want to try replacing the springs.. too many others had higher than normal results by changing them out.. King springs seem to be made out of spec?

So I added (tried 1/4" spacers first) 1/2 steel spacers and used 1/2 longer Grade 8 bolts, washers and nuts. There are two sizes, longer ones in the front that hold the shock mounts and the shorter ones on the sides. I just loosened the front ones and the ones on one side, then removed a side one to gain the needed room for the spacer.. replaced that bolt and then did the rest on that side.. repeated for the other side.

One photo shows the half inch spacers installed. the other the results with only 1/4 inch spacers. Car is now at correct height and I then adjusted the headlights to aim properly!!!
Hi Roger, I'm glad I found this old post on ride height. I am rebuilding all (4) corners of my 1985 S3 and just got the first corner put back together tonight. The car had no engine when I got it and it appears that everything that I've taken apart is original. I did not replace the springs and I have read on this forum and others that the LT1 is lighter than the original 4.2 DOHC, but I don't know by how much (one suggestion is 30lbs). I removed the (2) 1/8" packers and used 1/4" spacers on the spring pan. I have seen one formula that says 1/8" at the spring is about 5/16" at the hub. If so, I'll be about 1-1/4" lower. What are your thoughts on my decision?
Dave
 


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