Rear Lock Cylinder

This cylinder is located in the rear latch, pulling down the rear of the soft top. It is highly recommended to upgrade these actuators in pairs.

Convertible hydraulic cylinder rebuild/upgrade service for Mercedes R129 models 300SL, 500SL,  600SL, SL320, SL500, SL60, SL600, SL73.

Top Hydraulics Offers two options for upgrading cylinders for Mercedes convertible tops.

For Rebuilding The Cylinders That You Send In:  We gladly accept the cylinders in their locks/latches at no extra charge -- you save the extra labor and we have all the assurance that the cylinders do not accidentally get scratched upon removal from the locks.

To order with Core Exchange: Core deposits will be refunded in full if we receive your matching cores within 90 days, and the cylinder rods are unscratched. A small "rental charge" may apply if the cores get returned later than 90 days from receipt, but we are usually extending the return period within reason without such a rental charge.

Metal parts in your hydraulic cylinders do not get damaged during normal operation. Sealing surfaces (for example the polished, chromed cylinder shafts sliding through the rod seals) can easily get scratched beyond repair by tools - especially during DIY repair attempts. Top Hydraulics can replace any damaged metal parts but has to charge extra for that service.

Seals used by Top Hydraulics, Inc. include Viton™ and Teflon™-hybrid seals, as well as enhanced Polyurethane material, which far exceed the OEM's requirements for rigidity, but provide more than double the service life for your convertible car top actuators, based on scientific test data. Making your roadster/cabriolet hydraulics better than new!

Part Number - 1298002172 (AKA A129 800 21 72)

Please note that Model years 1990 and most of model year 1991 were originally equipped with p/n A1298000072 in the rear locks, which have 6-mm shafts and M5 threads at the ends of the shafts. For comparison, the shafts in the tonneau cover lift cylinders A1298002072 next to the rear locks have 6-mm shafts. The complication is that Mercedes would have sold p/n A1298002172 if anyone had tried to replace the rear lock cylinders with new ones from Mercedes. (The wisdom of that move alludes us, as Mercedes still sold the complete lock assembly with an A1298000072 in it.) P/N A1298002172 has a 9-mm shaft and an M6 thread at the end of the shaft. Thus, to install p/n A1298002172 in the rear lock of model year 1990 or 1991, you will have to tap an M6 thread where there used to be an M5 thread. Conversely, p/n A1298000072 can be installed into a lock that already has an M6 thread in it by securing it with two M5 washer and an M5 nut. If you have an model year 1990 or 1991, then best compared the shaft diameter of the cylinder in your rear lock to that of the A1298002072 tonneau cover lift cylinder next to it and order p/n 1298000072 (tonneau cover lock cylinder) instead if needed.

Mercedes R129 SL Years: 1990-2002

Rear Lock Cylinder Removal Guide