hi guys, just to tell you about the solution to the problem...
It was discovered that both rear springs were broken. I don’t know the reason, I think - the dying shock absorbers contributed to the destruction.
The urgent question arose of where to get replacement parts. This is not the case in the Russian Federation, except for 2-3 pairs of used. Ordering in the USA is also not the best option - your prices for parts have increased, and the cost of shipping is simply astronomical.
The decision was made to manufacture the springs directly on site. Well, in fact, Ekaterinburg is a city-factory. Missiles, tanks and self-propelled guns, sophisticated equipment are made here. It is unlikely that in such a city there will not be a specialist to make an ordinary pair of springs according to the sample. And Yes - of course it was found, after 2 days and 90 USD I am the owner of a pair of new rear springs made of spring steel. It differs from the original only in the thickness of the rod, 13 mm instead of 12.6 mm. It’s just that 12.6 was not available, but it seems to me that this is not critical.
I will keep you posted on the results of use.
And here are the pictures:

 

A good solution

 

That is a common failure. Seems to be in the exact same spot that they break.

 

Now I have another difficulty, it’s funny of course, but...
in short, the spring has different pitches of turns along its length. As I was told, this design is aimed at dampening vibrations of different intensities for maximum comfort.
I pulled my springs out without looking and now I don't know where the top and bottom are. Where should the tighter turns be? up or down?
If anyone knows, please let me know.

 

I place the tighter turns at the top, unless the instructions say otherwise.

 

I had the same problem. I put the tight end up. They are called "progressive".

 

Good looking spring. More coils should compensate for the thicker wire and give close to the same rate or a little softer. The progressive pitch can sometimes result in a little banging sounds as the tighter coils come into contact. Harmless but annoying. I've seen aftermarket springs with rubber dampeners to counter this.

The additional coils could results in earlier bottoming, if the snubbers aren't long enough.

Very interested in hearing how they work. Best of luck!

Remove one coil and you might have the perfect aftermarket "lowering" spring. Very popular in the states to lower the rear of the HHR a bit to make it appear more level. Little prictical value, just appearance.

 

You can not remove a coil from either end of the rear springs as the pigtail will be removed and the spring won’t be located correctly in the spring perch.

 

Of course not. That's not what I meant. I meant removing it from the design.

 

Just to let future readers know.