Nissan Z32 300ZX Brake Master Cylinder Upgrade. This brake master cylinder upgrade will provide proper brake bias. It will move more fluid with less pressure allowing the master cylinder to move the 26mm or 300mm front 300ZX 4 piston calipers efficiently. Pedal feel will greatly improve giving the driver better pedal modulation. For the ultimate brake upgrade, use this brake master cylinder with an automatic 240SX brake booster or a 300ZX brake booster and all around 300ZX brakes with stainless steel brake lines. How does this BMC help? Here's how it works: Since 4 piston calipers are more responsive and require less pressure to work efficiently. It will need a bigger piston inside the brake master cylinder. Small piston diameter gives more pressure versus bigger piston diameter. If the calipers are forced with too much pressure, it will lock up too quickly giving the driver no room for modulation. This brake master cylinder comes with the middle fitting that is used for NON-ABS equipped 240SX only. Only for LEFT HAND DRIVE vehicles.