DUAL CIRCUIT MASTER CYLINDERS
If you are installing disc brakes to all four wheels, the use of this master cylinder is mandatory.The stock master cylinder cannot supply the additional pressure or the correct bias needed in a 4-wheel disc brake application. The answer is EMPI's larger 20.6mm bore Dual Circuit MasterCylinder. This master cylinder will fit Super Beetle only. Will not fit Standard Beetle.

17-2808 - 20.6mm Dual Circuit Master Cylinder (Super Beetle Only), Ea
Ref P/N: 133 611 015HDD

WARNING: It is extremely important that brake lines be installed by a trained mechanic. Proper length of each line in relation to wheel travel and steeringangle is critical to avoid brake failure. Equally important is brake lines must be free owing and have no contamination. Additionally, all calipers must be bledproperly, regardless of kit purchased. Do not attempt brake line or caliper installation without the experience to properly evaluate all of these issues