OEM Hydraulic Throw-out Bearing / Concentric Slave Cylinder (CSC) assembly found inside the bellhousing of the transmission.

These are found on all manual 6MT Zs and Gs equipped with the HR or VHR engine.

This part is prone to failure when upgrading to a performance clutch or simply due to excessive heat during track use.  Z1 Motorsports offers a bolt on kit to eliminate the stock internal slave cylinder and replace it with an easily replaceable external slave cylinder. Z1 CSC Delete Kit

It is recommended to replace the Master Cylinder any time a factory CSC is replaced.  This hydraulic system has proven subject to more contaminants and heat than other vehicles in our catalog.  The master cylinder is often clogged due to this issue, traits of this problem are always a freshly replaced slave cylinder that will not bleed completely.  Do yourself a favor and add a new replacement master cylinder to your order prior to shipping along with high temp brake fluid.