Rear Ride Height Has Dropped

Keggers · Dec 30, 2004

After a long trip with the back loaded to the absolute brim with gear my right rear seems to have dropped about 3/4 of an inch (relative to the height it used to be and to the left rear). It was sitting low when it was loaded up for the trip and doesn't seem to have ever recovered since. Also doesn't seem to have the bounce on the right that it does on the left any more.

Has M030 adjustable Koni's on the rear - from memory they are about 5 years and 40k miles old. Assume it isn't just that it needs adjustment as I thought this doesn't affect ride height, just stiffness?

A couple of questions:

1. Is this likely to be caused by the damper having worn out?

2. If it is, is this something I can do easily enough at home with a good jack and axle stands and a bit of elbow grease?

3. Is there anything else obvious to replace/adjust at the same time if I did it myself?

Thanks

carlmthompson · Dec 30, 2004

You could try checking that the spring hasn't snapped. More possible in the cold weather.

colinbythesea · Dec 30, 2004

Just to second the checking the spring hasn't snapped. I had this happen on a 924. Looked at it on the drive and one side was lower. When replaced the spring had a crack right through the middle, most of which was rusting so it had been like it for some time. The final bit that was holding on was visible and sheared straight through due to taking all the strain.

Keggers · Dec 30, 2004

Ok, showing my complete lack of knowledge here, but when you talk about the spring being cracked, is this inside the koni shock absorber or am I completely misunderstanding the term spring (or not looking hard enough when I poke my head underneath!)?

carlmthompson · Dec 30, 2004

The spring (i think - I haven't looked recently and can't quite remember!!) fits over the top of the shocker. If it's not there this could be the problem[

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Normally it's the ends of the spring that crack (they rust), but as Colin suggests, they can also snap in the middle! If it's snapped in the middle, then it's best not to drive the car. If it's the ends, you need to get it replaced ASAP, and normally you would replace in pairs.

Fen · Dec 30, 2004

Er, no it doesn't, not on the back.

The spring on the back is a torsion bar that has one end in the rear swin arom in front of the back wheel and it extends off across toward the middle of the car where the other end is.

carlmthompson · Dec 31, 2004

Of course they are!

Perhaps I had just forgot which way I had parked it in the garage.

Maybe it's because there's no headlights at the front for me to get my bearings.

I've put a Tommy Tippie steering wheel in the back for just those occasions, although I find the steering response not as good [

]

PS Colin - Principles about the springs are the same - no matter where they are[

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Keggers · Dec 31, 2004

So does this mean that there is a chance that the torsion bar has snapped then?

That gets into expensive territory doesn't it?

sawood12 · Dec 31, 2004

Keggers,
When I bought my car the previous owner mentioned that in the previous year the rear suspension had dropped on one side. It turned out that the torsion bar had indexed round or slipped at the fixed end i.e. the end that connects to the car body. They re-indexed the torsion bar but warned that if it happened again it could require a new torsion bar (probably best to replace as a matched pair as with most of these things). Apparently the splines at the ends of the torsion bar can wear and replacement is the only option.

If this is the problem you've got then as far as i'm aware it is a pretty specailist job and is probably best left to Porsche specialists or very experienced DIY mechanics. I can dig up the receipt my previous owner if you want but from memory it wasn't a particularly expensive job.

Touch wood mine has been OK so far since I've been running it.

Good luck with yours.

Keggers · Dec 31, 2004

Cheers Scott. Sounds quite like that may be what has happened. Due for an oil change etc anyway so will get someone to take a look at the same time.

Have just spent an hour or so on google learning about torsion bars and how they work etc., so at least if nothing else i'll come out of this understanding how my suspension works a hell of a lot better than I did before!

Diver944 · Jan 2, 2005

Greg, it may not be as bad as that. The rear ride height is adjustable via an eccentric bolt. It 'could' just be that this bolt has loosened when you overloaded the car and it's now sitting on it's lowest setting. Look at the picture below and David Sims website for more info: http://dialspace.dial.pipex.com/prod/dialspace/town/pipexdsl/s/asco96/944t/suspension.htm#Ride%20height

colinbythesea · Jan 3, 2005

ORIGINAL: Keggers

Ok, showing my complete lack of knowledge here, but when you talk about the spring being cracked, is this inside the koni shock absorber or am I completely misunderstanding the term spring (or not looking hard enough when I poke my head underneath!)?

The spring is a "torsion spring" so it works by twisting a long round metal bar. Unfortunately you can't see them as they are inside the tube that runs from one side of the car to the other in front of the rear wheels.