The H&R 29739-4 is a set of sport lowering springs for the 1995-1999 Mercedes-Benz W140 S-Class, specifically the S320, S400, S420, and S500 models with self-leveling suspension built after 1/1/95. Its progressive-rate design is the main reason to choose it over stock. Owners on user forums say it firms up body motion and cornering response without the harsh ride of linear sport springs. The main cheaper alternative is cutting the factory coils, which many owners on user forums warn against because it can compromise ride quality and spring seating.
Ride height on this platform depends on both the spring and the rubber spring pads. Owners on user forums report that the pads come in 8, 13, 18, and 23 mm thicknesses, and that switching to thinner pads lowers the car roughly one-for-one. Because the self-leveling system resets height, one owner found the car rose back to stock height at startup until the leveling valve linkage was adjusted under the rear. Use proper spring compressors, since the coils carry heavy preload. Long-tail searches for W140 S500 self-leveling sport springs, 1995-1999 S420 lowering springs, and W140 lowering without cutting coils match this application.
The product is specified for self-leveling models built after 1/1/95. Confirm fitment with the manufacturer before ordering for a non-self-leveling car.
Owners on user forums report the car can return to stock height at startup if the self-leveling valve linkage is not adjusted. Setting the linkage is part of a proper install.
Many owners on user forums advise against cutting coils, citing ride quality and spring seating concerns. A matched sport spring avoids that compromise.
Owner opinions on user forums differ. Some keep the factory shocks and report a comfortable ride, while others pair the springs with aftermarket dampers. Confirm damper recommendations with the manufacturer.
This is a moderate-difficulty job that requires spring compressors, jack stands or ramps, and basic suspension hand tools. Owners on user forums recommend choosing spring pad thickness before reassembly, since pad selection sets final ride height. After installation, adjust the self-leveling linkage so the car holds its lowered height after startup, using the 10 mm nut on the rear leveling valve arm. Do not cut the springs as a shortcut. Owners on user forums warn that compressed coils can cause serious injury if handled without the correct tools.
