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Cause of sudden ride hight and camber change.

 
Old 06-08-2005, 12:43 AM
  #16  
ROG100
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Hi Andrew,
Good meeting you at SITM.
Ride height was measured with nothing in the car, apart from stock equipment (tools and spare).
Full tank of gas.
Ride height was measure accuratly at the correct points.
No broken springs and all looks original, however 84k miles.
Ernest,
I will post pics of the Kumohs tomorrow.
They are toast mostly, $300 and new on Friday and dead by Monday.
Jim M test drove the car at amazing speeds on some of the great roads over the weekend. Held up pretty well apart from some wallowing of the shocks.
This is looking like a new set of springs and shocks all round plus new tires all round.
The car is up in the air (on a Kwick Lift) and will stay there until the problem is solved, so no chance of any damage.
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Old 06-08-2005, 12:46 AM
  #17  
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Nicole,
I wish I could explain it with a weight gain.
That would be to easy and lots less expensive to rectify.
Mind you I did eat pretty well at SITM.
I will check the scales in the morning.
Roger
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Old 06-08-2005, 12:51 AM
  #18  
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Maybe your spring adjusters have been backing off with vibration and driving?
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Old 06-08-2005, 03:16 AM
  #19  
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Don't the WSM's have an unloaded spring heigth?
If you can't adjust your way out of the situation ...yank em' and measure.
If you are within spec it's gotta be yhe shocks.
Unless you have a teenager who jumps curbs, drives down steps ...
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Old 06-08-2005, 06:08 AM
  #20  
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Originally Posted by ErnestSw
Interesting. Wouldn't the RESTING height of the shock remain the same? I assumed that the shock would end up whatever length the spring height dictated in a coilover.
The gas pressure exerts some lifting force. Until it doesn't.
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Old 06-08-2005, 07:23 AM
  #21  
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The non-role of the shocks re. static height is generally agreed. There are exceptions, as jp noted re Bilsteins - they are a mono tube shock, so as the gas charged chamber expands when heating, the piston static height can increase. Installed heights can also be marginally higher - but by only a few mm.
When I installed Konis (gas) to replace the Boges (gas) in the S4 this year, the suspension heights went up an exact 5mm at all corners - from 165mm to 170mm . Impossible - since they are both dual tube gas charged designs! Of course it was - I simultaneously installed 17" wheels and tires to replace the worn out 16" OEMs: the 5mm increase was due to fresh, deep treads and slightly larger tire diameters .... the point is that fresh Konis did not alter heights by even a mm over Boges with 60KKm on them.

At an average of 130 mm suspension height, your car is ~ 40mm too low from the minimums recommended in the WSMs. There is very little compliance left in the suspension, and desired alignment settings 'may' not be achieved.
Before doing anything drastic, I'd crank away at all the adjusters to get in the 170mm range. Drive on the old tires and check shock/spring action to see if replacement is warranted. Following that decision, realign the car and proceed.
BTW - any comments on the tire wear pattern ( pics?)
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Old 06-08-2005, 08:49 AM
  #22  
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What else might be affecting this? Bushings, Bent control arms , bad shock tower mounts? I think these are all suspect as it's hard to believe that the springs would loose that much ride height. I can see 10mm or so, but 40mm is pretty remarkable. My 82's front ride height (non-adjustable) has only lost 10mm iover the past 23 years. But then I don't track the car, just normal driving and the occasional twistie at SITM . Do you track the car ever? If so, then maybe youhave worn out the springs. Hmm.... Please keep us informed on what you find out.
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Old 06-08-2005, 09:13 AM
  #23  
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Thank you all for your interest and comments.

The car has never been altered in any way to my knowledge.
Shocks are Boge and the springs are blue dot.

I have never tracked the car and am mostly a cruiser and not a spirited driver.

See pics below:
LR
RR
Both Continentals with about 4000k miles. Wear is severe on inside edge due to high degree of camber.
FL
FR
Both Kumoh's 712, fitted on Friday on the way to SITM due to a flat on the front. They have done about 1500miles. Less than 50% tread left.

Two pics of the camber. The spirit level in the last picture IS vertical. Difficult to hold the level and take the pic.
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Last edited by ROG100; 07-28-2009 at 05:08 PM.
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Old 06-08-2005, 09:44 AM
  #24  
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More information:
Shocks are gas filled Boges.
Springs are two dot blue.
Cosmoline is still on the springs.
Rubber mounts on top of the springs look perfect.
I am pretty sure this is the original stock setup.

Pics:
LR spring
RR spring
Kwick-Lift
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Last edited by ROG100; 07-28-2009 at 05:08 PM.
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Old 06-08-2005, 10:04 AM
  #25  
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I don't see anthing broken or out of place. Obviously your camber is WAAAAAYYYYYY off on the back. Maybe the PO set it up like this for track events? But the real question is, Is the camber set to this or have the wheels settled to this position because of some other reason? Hmmm...

I guess the first thing to do is to get it to the proper ride height. You've still got quite a bit of travel on the adjsuters, so first step is to crank those up. Then I'd check to see if the camber profile is more appropriate or if adjustment on the camber eccentric is needed.

It'll be a fair bit of work (ask TEREK), but something you can't let go. Hope this helps.
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Old 06-08-2005, 10:10 AM
  #26  
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Andrew,
I have had the car for two and a half years. The tire wear and camber excess have happened within the last six months. Nothing has been done to the car to cause this.
Pictures of the rear end of my car a year ago show no visible camber.
I will crank the adjusters up this afternoon, however even if I can achieve the correct ride height/alignment it is still concerning me as to WHY this happened in the first place.
I will probably fit new springs and shocks anyway.
We are setting up to do the alignment ourselves ala Earl Gilstrom.
Going to raid Harbor Freight today for the slip plates.
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Old 06-08-2005, 10:26 AM
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Roger-
I heard you talking about doing the DIY alignment. Hope it works well for you. As to the why, well I don't see any obvious reason. When you go to pull the shocks, it should be pretty obvious if there is any damage to the spring/shock assembly. You may want to see about getting a stiffer set of springs (I don't remember the color codes off hand, but I'm sure DR or 928 Int'l can tell you). Don't forget to inspect the upper and lower control arms and their bushings as these could also affect ride height. Other than that, I'm at a loss. Have fun at harbor freight.
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Old 06-08-2005, 01:12 PM
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Roger the picture of the front tires indicate a very bad toe setting. Note how the edge of the treadblocks show a slight "lip" or feathering along the same side of the blocks and sips. Excessive negative camber would not wear out the front tires that quickly I run about 3 1/2 negative on the old brown 1980
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Old 06-08-2005, 01:56 PM
  #29  
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[QUOTE=Jim bailey - ... Excessive negative camber would not wear out the front tires that quickly I run about 3 1/2 negative on the old brown 1980 [/QUOTE]


JB;

What is the camber AFTER you get in the car??

Sorry, couldn't resist

Scott
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Old 06-08-2005, 02:08 PM
  #30  
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Roger,
I emailed you my ride height from all four corners.

I would not recommend to start playing with the setup without getting it checked out. Put it on an alignment machine and see what is really going on!

Actually I checked my GTS rear camber withyour level method and I'm not that far off from yours. If your tires wear so quickly and unevenly I think the problem is a camber/toe combo problem.

I agree with Jim.

Get the car aligned first and get the worn tires shaved again to make them even. Drive your car and re-check.

If you start playing with ride height setups and so on you could possibly turn things to the better. But also you could get things further out of alignment and when you finally go for a 4 wheel alignment you don't know what the first cause of the problem was..
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