Hirsch suspension problem?

[RussJ]

I have an '04 Aero estate fitted with the Hirsch suspension upgrade which has now done about 50k miles - car is at 80k.
Generally, I've been delighted with the setup and found it a great improvement over standard.
However, over the last month or so, I've started to notice that the car seems to be riding a lot harder and crashing into road defects rather then absorbing them as before. A quick look underneath hasn't revealed anything obvious (broken spring or shock leaks) so I 'm begining to wonder if its just me getting older! I'm currently on Conti 3 XL's at factory pressures so I don't think its a tyre issue.
Are there any bushes that could fail and give these symptoms? The large rear arm bushes were replaced when the suspension was fitted. Is it likely that the Hisch shocks are starting to fail? All suggestions or ideas gratefully received!
Russ

[Norfolk Jim]

I must admit when i sold mine Russ the ride did seem harsher than when it was fitted and mine had only done 20k. I sometimes think its the temperatures we are having.

Some days mine seems more comfortable than others and its on standard sports suspension. Normally though I find that after a decent drive it does feel more comfortable and wonder if its due to everything being 'warmed up'.

Now I have my winter wheels on the tyres definitely don't seem to be as hard in the cold as my 17" Contisport 3's so perhaps you are feeling this difference? I would be absolutely gobsmacked if they were failing but surely that would make it a little more bouncy/springy rather than harsh?

[sgould]

I've known a couple of Hirsch shock absorbers fail near 60,000 miles, but both have been leaky.  Neither were mine, so I can't say for sure what the full problem was, if any, other than wear and tear.

I've done 63k on my Hirsch set-up and it seems OK at the moment.

[phoenix]

And my Eibach suspension (same shocks, possibly different springs) has done over 80k without problems (there's chancing fate!)

[Geoff1951]

I put Hirsch suspension on my 9-5 at 70k, it's now done 99k. I do feel the undercarriage works better after a few miles when it's warmed up, as Norfolk Jim says above.

[RussJ]

Thanks for all your comments and suggestions. It is true that I'm only doing short journeys these days so the suspension and tyres don't really get a chance to warm up.  We're due to go on a couple of longish trips shortly so it'll be interesting to see if things improve.
Russ

[RussJ]

I have found the answer - go for a drive in my wifes Smart Brabus.
Its stiff springs and wide low profile tyres crashing over what passes for roads in Norfolk make the Aero feel like a Rolls!
Russ

[Max Headroom]

Smart Brabus - I always liked the look of those

[sgould]

SWMBO had a quick look at one of those.  She looked at the pics and saw some Smart cars and wasn't sure.  But the deal breaker was when she realised that they were sold by Mercedes dealers.

She used to have a Merc..... 


..... memories are long!!

[RussJ]

Chatting to the Mrs about this problem and whether I was just imagining things, she reminded me that we had recently transported about 250kgs of firewood briquettes home about 30 miles and I wondered if the load could have partly crushed the "progressive" springs?
This might explain the excessively hard ride and lack of compliance.
Do you think that such a load spread out over the whole of the load area, ie rear seats folded down, would be enough to squash the springs permanently?
As far as I remember, the standard load limit was about 575kgs for the estate.
I guess the only way I can be sure is to take one out and measure it?
Anyone know what the new uncompressed length should be?
Russ

[Norfolk Jim]

Russ - That's no more than 3 large adults really & I've had more weight than that in my estate - floor tiles and several boxes of them. Slightly bouncy ride but went back to normal. Don't think it's possible to over squash a spring?? Your bump stops would hit first surely.??

Factor in 3 large adults plus luggage and you should be able to tow a caravan so further 75 kg on tow bar..........

[phoenix]

Chatting to the Mrs about this problem and whether I was just imagining things, she reminded me that we had recently transported about 250kgs of firewood briquettes home about 30 miles and I wondered if the load could have partly crushed the "progressive" springs?
This might explain the excessively hard ride and lack of compliance.
Do you think that such a load spread out over the whole of the load area, ie rear seats folded down, would be enough to squash the springs permanently?
As far as I remember, the standard load limit was about 575kgs for the estate.
I guess the only way I can be sure is to take one out and measure it?
Anyone know what the new uncompressed length should be?
Russ

Kerb weight ranges from 1525-1665kg for the saloon, 1590-1740 for the estate, gross weight is 2060-2110kg and 2130-2180kg respectively. That give a max load of around 445-525kg for the saloon and 440-540kg for the estate. You have to guess at what contribution engine/trim makes to the kerbweight but it would seem logical to say that the heaviest engine would be the 3.0D and heaviest trim Aero with vented seats.

Anyway, I certainly wouldn't worry about that weight. Last Christmas (Wham!) I ferried home a cubic metre of hardwood logs. I worked out that it was probably in the region of 450-500kg, plus myself. The car was fine, albeit a little slower than usual

[RussJ]

Just had an email back from Hirsch confirming that the load rating of their springs is exactly the same as standard Saab items.
Looks like I haven't overloaded it then...
I'm still sure something isn't right though but I can't think what else it could be?
Russ

[RussJ]

Sorry to keep banging on about this but I thought pictures might help.
This was with nothing in the boot and the suspension resting on an axle stand, ie normal loading.
It looks odd to me that the first few coils are all squashed together and aren't going to be contributing much to the ride.
All the compliance will be down to about half the spring?
Is this normal?
Russ

[sgould]

How much of the rest of car is on axle stands?  If it's just that corner the spring there will be taking more than its fair share as the opposite side will be part unloaded.

I only have a picture with the spring fully unloaded.