THIS IS FOR THE O-RING SEALS INSTALLATION GUIDELINE PLEASE READ This hydraulic cylinder repair kit is not sponsored or endorsed by Porsche in any way. The kit is and aftermarket product designed and produced by Wesbaun Consultants Inc to repair the failed, leaking Porsche Cylinders that Raise, lower Lock the convertible roof into position. The kit includes seals which are a direct replacement for the failed urethane OEM u cup ROD seals. Porsche will tell you the cylinders cannot be rebuilt and will want to sell you a completely new cylinder costing $$$$. All hydraulic cylinders in vehicles or machinery you come across can be rebuilt. Thats why there are many companies out there that manufacture replacement seals. If you are competent with the use of basic hand tools this kit is a DIY project for you and will save you $$$$ We will not be found responsible for misuse, misinterpretation and poor workmanship when installing the seals. Correct installation is responsibility of the Buyer, we are not responsible for the outcome of installations performed by third party installers like your mechanic. If you do use a mechanic please ensure he has carried out this installation procedure competently before The o-ring in the kit is an upgrade to the OEM seal, which is not capable of withstanding the aggressive/corrosive hydraulic fluids. The Nitrile Rubber compound used in this seal is exceptionally resistant to petroleum based oils, found in hydraulic fluids used in the convertible top hydraulic system. Fits the following vehicles 1999 012 911 (996/997) Convertible A Multi Page Illustrated Guideline is included and Seal tool. For repair of Porsche part numbers: 99656194501 Additional Details ------------------------------ Product description: THIS IS FOR THE O-RING SEALS INSTALLATION GUIDELINE PLEASE READ This hydraulic cylinder repair kit is not sponsored or endorsed by Porsche in any way. The kit is and aftermarket product designed and produced by Wesbaun Consultants Inc to repair the failed, leaking Porsche Cylinders that Raise, lower Lock the convertible roof into position. The kit includes seals which are a direct replacement for the failed urethane OEM u cup ROD seals. Porsche will tell you the cylinders cannot be rebuilt and will want to sell you a completely new cylinder costing $$$$. All hydraulic cylinders in vehicles or machinery you come across can be rebuilt. That?s why there are many companies out there that manufacture replacement seals. If you are competent with the use of basic hand tools this kit is a DIY project for you and will save you $$$$ We will not be found responsible for misuse, misinterpretation and poor workmanship when installing the seals. Correct installation is responsibility of the Buyer, we are not responsible for the outcome of installations performed by third party installers like your mechanic. If you do use a mechanic please ensure he has carried out this installation procedure competently before The o-ring in the kit is an upgrade to the OEM seal, which is not capable of withstanding the aggressive/corrosive hydraulic fluids. The Nitrile Rubber compound used in this seal is exceptionally resistant to petroleum based oils, found in hydraulic fluids used in the convertible top hydraulic system. Fits the following vehicles 1999 ? 012 911 (996/997) Convertible A Multi Page Illustrated Guideline is included and Seal tool. For repair of Porsche part numbers: 99656194501