The Porsche 996 (911) turbo is an exceptional piece of automotive engineering as is evident by its years of success in the market place and its history of winning and dominating in the many different racing series and competitions around the world.
As such repairs and upgrades to this fantastic car must be approached a bit differently than other vehicles. The way the many different components and systems of the car are designed and function is a bit different than the typical every day car and as a result it requires expert knowledge and understanding to perform upgrades and maintenance on these vehicles.
Here we’ll target the Porsche 996 clutch and related repairs.
For instance the clutch system in this car is unlike other vehicles on the market. The clutch on the Porsche 996 turbo is hydraulically assisted so that even when high clamping load pressures plates are installed the pedal effort does not change. The biggest difference in the system compared to other cars is in the design of the slave cylinder. The hydraulic assist system works by using the high-pressure circuit of the power steering system to charge an accumulator that’s a part of the slave cylinder assembly in order to reduce the effort required to operate the slave cylinder.
A good and detailed understanding of this system is required in order to perform work such as clutch component replacement correctly and according to factory specs.
Another big difference in the way the clutch system works in the 996/997 turbo compared to other cars is the pressure plate release mechanism. The majority and most common way of pressure plate release operation is push-type while on the Porsche 996 turbo it is a pull-type. While this may sound like a very small and minor detail, it isn’t so as the procedure required to detach the gearbox from the engine is completely different. The biggest and most difficult aspect of the job becomes removing and reinstalling the pivot pin that the release lever attached to the throw-out bearing operates on. This pin must be removed (slid-out) before the gearbox could be detached, and must be put in during the assembly after the engine and gearbox have been mated. If you have ever seen this assembly you would understand how difficult is it to line up the holes on the release lever with the ones on the bell-housing as there is no way to actually see them and must be done by feel. Furthermore the pin has roller bearings on both ends which house small steel rollers inside and can slide off the shaft if it is pulled back during insertion. If this happens the gearbox will need to be removed again in order to retrieve the rollers and assemble the bearings.