10 yr old Bilsteins causing sagging rear suspension???

pmansson

pmansson

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I am in the process of adjusting the rear height on one of my cars. After slight shortening of original springs, and refitting the 10nyr old shocks, and 2 dot pads, I got the car back on the ground. I bounced the rear end up and down a few times, and sat on the edge of the trunk panel.
i then measured the height which was just right.
but after driving home a few miles, I measured the height the following day. It was almost an inch lower!
The garage guy thought it might be the 10-12 yr old shock absorbers which dont hold theirbresting height. Perhaps change for another set of Bilsteins...?
i have an equally old set which have never been installed.
any thoughts or suggestions...?
Peder
 
Agree with deQ.......shocks dampen, springs support. Your pads may have settled in or based on the erroneous comment your guy said, installed improperly.
 
He cut his springs........
I cannot recall who I spoke with, I think CN who said (paraphrasing) "I can count on one hand, the number of times I have seen springs fatigue and still have five fingers".
On the other hand, for those of us who own early X3's, the springs crack routinely.
 
IMHO, fresh Bilsteins have enough internal gas pressure to raise your ride height a small amount. IIRC, it takes between 25lbs and 30lbs of force to get each shock/strut to start to compress. Times two, it’s only 50-60lbs So the change in ride height should be very small (but perhaps visually noticeable at the rear where you have lower spring rates). I have a small car where 60lbs of upward force would raise the car about 1/2”.

This is my recollection from putting Bilstein HD’s into my 2002’s and E3’s nearly 40 years ago.
 
bavbob said:
He cut his springs........
I cannot recall who I spoke with, I think CN who said (paraphrasing) "I can count on one hand, the number of times I have seen springs fatigue and still have five fingers".
On the other hand, for those of us who own early X3's, the springs crack routinely.
Click to expand...
Every Mercedes SUV we’ve had in the past 20 years has had rear springs break after 5-6 year in service. They always break just beyond the first coil. I don’t think they are using more salt on the roads. I do think the anti-corrosion coatings being used are less robust (but more environmentally friendly).
 
A cut spring will sit on one very sharp end, compared to an uncut spring which rests on the entire circumference of the spring.
So since they're cut, it could have eaten through the rubber pads quite easily, resulting in a very quick additional lowering of the car.
Just a thought.
 
Sorry for being unclear.
of course the springs determine the height. My question was simply if old, but little mileage shocks can sink down 0.5-1 inch after a normal short drive.
I will change them next time at the garage in southern Sweden, and report back.
 
I agree with Gransin, the original spring sits on a large area, cutting it just can’t be right as they will then have a sharp end vs the original shape which is designed to spread the load over a large area.
Do springs wear, not sure.
Do they break, well yes on modern cars. They usually break at a point just after the support which is the point where they flex but are also subject to corrosion from sitting in the damp from the mounting cup. Got this information from a Mercedes workshop manager when my Audi started to break springs. Pot holes and low profile tyres don’t help either.
 
Cornishman said:
cutting it just can’t be right as they will then have a sharp end vs the original shape .
Click to expand...

Depending on the style of spring perch, when you cut a spring you are supposed to finish by heating up and bending over the last 1/2 coil up to touch the next coil. I always shape the cut end to avoid creating a stress riser at that contact point (eg leave it a sharp end). You can also flatten the bottom somewhat with a belt sander running 36 grit or an angle grinder, if needed.

No, I don’t know if the OP did any of this.
 
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