spring mystery
 

Yesterday I was at the junkyard and pulled suspension springs off of a 380SE for my W123 300D suspension project. When I got home to measure them, I found that they are way shorter than any of the test values listed in the 126 or 123 FSM and don't have a part number that I can find.

The test values for these front springs are d=17.55mm, L=407mm. The unsprung length of 407mm is way shorter than anything listed in the FSM. Does this end cut with two hash marks and ground down end look familiar to anyone as aftermarket or a cut MB spring? I've attached a shot of a known MB 126 321 18 04 spring for comparison. The car also had these 16" wheels on it (which I took 2 of the 3 remaining), so maybe an upgrade package?

I'm just trying to figure out what the spring rate is, because I want to compare with what is currently on my car.

Thanks!

sorry
 

but is the one on the left factory? that is my guess. the one on the right, then is the cut one, lacking the ground edge and hash marks cause they got cut off.

the wheel is a euro wheel.

tom w

The one on the left is the spring in question (with the hash marks). The one on the right is a stock 126 321 18 04 spring. It does look like it was cut by someone with the perpendicular cut. But, the part number is at that end and the unsprung length (L) coincides with the FSM test value.

The one on the left does not have any part numbers that I can find, so I'm wondering if anyone has seen one of these before and know what they are. Otherwise, I guess I'll just try them as is.

Thanks

brian carlton
 

is the most expert on rear springs that i know of.

tom w

Dave ..... Here is a "magic" calculator for calculating spring rates. It works because all steel springs have similar constants.
http://www.proshocks.com/calcs/coilsprate.htm