How to rebuild main hydraulic cylinder? | Mercedes-Benz Forum Tell me please how to rebuild main hydraulic cylinder. (like this one R129 SL320 SL500 SL600 500SL 300SL Convertible Top Cylinder 1298000272 | eBay). hello and welcome best to send to Top Hydraulics the front are easy as, you wont be able to do the main ones unless you have a workshop...