We have fixed a ton of these on both W124 and W210 in our collision center. The factory caulk holds moisture which causes corrosion between the frame rail and spring perch metal. The metal separates and the tension of the spring causes it to bend upwards. Very dangerous! Anyone who states that this couldn't cause a hazardous traffic condition is nuts!

Anyhow, the fix is to remove the springs, air chisel out the old perch, grind to bare metal the area of attachment to the frame rail, weld in the new perch, caulk and apply wax sealant, then reinstall. Finally, the factory paint plus clearcoat is applied to the area. It's about a 2-3 day turnaround and costs typically around $300-$400 with parts, labor, materials.

Satish