1997 Mercedes R129 SL600 rear ADS sphere replacement
mahunt replaced the rear hydraulic spheres on his SL600 after harsh impacts over painted road lines. His account describes access around the exhaust, replacement-part date stamps and an unresolved disagreement over hydraulic fluid.
Why the owner replaced the rear spheres
mahunt reported that his SL had become harsh over painted road stripes and decided it was time to replace the rear hydraulic spheres. In a later reply he identified the car as his 1997 SL600. The thread records his assessment, without a separate diagnostic test or an explicit post-replacement ride-quality measurement.
Access details reported for this car
The owner removed the trunk contents and spare, worked toward the spheres from below, then reached them through the trunk. For the passenger-side sphere, the post mentions an 11 mm flare-nut wrench still attached, a 17 mm flare wrench for the large nut and three 10 mm hold-down nuts. On the driver’s side, the owner said the muffler had to be separated and the driver’s cross brace lowered; a resonator-delete pipe could remain in place on this particular car. These observations do not specify the full depressurization, support or removal procedure.
Parts and reported completion
He had fitted Febi spheres in 2019. When removing them for this replacement, he found a 2017 manufacturing date and joked that they had reached six years only on that basis. That is different from six years in service. The replacement spheres, which he called “Cortico,” carried a 2022 date stamp. He reported about four hours of work on Sunday and no issues during the replacement.
The thread does not settle the hydraulic-fluid question
mahunt said he used the remaining MB ZHM fluid, then topped up with Pentosin CHF 11S from a Mercedes-Benz can. He later reported using CHF 11S in the ADS II system since 2019 without adverse effects he had noticed. Frank_S500 challenged the choice and emphasized matching the fluid to the particular system. AndreasHannover said the R129 uses ZH-M, contrasting it with the R230, and linked a Mercedes fluid sheet. sushipaste identified specification 343.0 ZH-M for the ADS and soft-top reservoirs. These are the contributors’ statements; the thread contains no independently verified compatibility finding or agreed resolution.