The Bilstein B4 24-013161 is a rear replacement shock from Bilstein's B4 OE line, built as a gas-pressurized 36mm monotube damper with a stem upper mount and an eye-style lower mount. It is aimed at the Mercedes-Benz R129 SL chassis, specifically rear axles without self-leveling suspension. Original units lose their gas charge as seals age, and a worn shock lets the rear end bounce and wallow. A new B4 unit restores that control at a lower cost than a full strut-and-spring overhaul, and it is a direct bolt-in for a Mercedes-Benz 300SL R129 rear end. Search terms buyers use include R129 300SL rear shock replacement, B4 OE monotube gas shock, and SL rear shock without self-leveling.
Fitment is catalogued for 1990-1993 300SL models, with the same part also listed for 500SL, 600SL, SL320, and SL500 applications in the B4 series. Mercedes-Benz OEM numbers cross-referenced to this part include A 129 320 00 31 and A 129 326 02 00, and the old Bilstein part number F4-B36-1316-H1 is also listed. Confirm your chassis serial number and rear suspension type before ordering. Replace both rear shocks together to keep handling balanced, since the shocks work as a pair.
No. The application data for this part is limited to rear suspension without self-leveling. Vehicles with self-leveling need a different shock, so confirm your suspension type before ordering.
User forums report that a spring compressor is not needed, because the rear shock is a separate unit from the coil spring. Owners on user forums say the job is straightforward once the trunk trim and lower control arm cover are removed.
Owners on user forums describe this as a manageable driveway job with basic hand tools. Work from the trunk to free the upper stem nut, which is commonly described as 17mm, and hold the shaft with vise grips so it does not turn. At the lower control arm, the original fasteners are commonly reported as 17mm, though one replacement set reportedly used 16mm, so have both sizes on hand and confirm before starting. Soak the lower bolts in penetrating oil for a day or more, since they can seize. Some owners find the rear seat and trunk trim are the hardest parts to remove. Confirm the correct torque specifications with the manufacturer, because published values vary.
