I had one front spring broken on my 1992 500SEL and didn't even know it. I even towed a 2000lb boat with the car before I found out it had been broken all along.

Mechanic showed me the spring (it was definitely broken) but the ride height problem wasn't visible to the naked eye, either before or after the repair. I'm sure it was different - don't get me wrong - but I just couldn't see it by looking casually at the car (it didn't lean in any direction).

The amazing thing is, the car handled just fine before I had the spring replaced! Even while towing a boat, I didn't notice a difference.

So definitely look at your front springs. I was told this is a very common occurrence with older W140's because they are so heavy.. don't know if it's absolutely true, but it sounds quite logical to me.

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'83 300SD 335,000km (207k) mi SOLD
'87 560SL 163,000km (101k mi) SOLD
'86 300SDL 356,000km (220k mi) SOLD
'92 500SEL 250,000km (155k mi) SOLD
'90 300SL 140,000km (87k mi) SOLD
'01 S430 260,000km (161k mi) SOLD
'03 SL500 167,000km (104k mi) SOLD
'07 S550 4MATIC 235,000km (146k mi) SOLD
'07 GL320 CDI 4MATIC 348,000km (215k mi)
'13 GL350 BlueTec 4MATIC 170,000km (105k mi)
'14 SL550 72,000km (43k mi)