22mm Buggy Master with Billet Reservoir

OVERVIEW

When you are pushing the limits of your off-road machine or upgrading your street-bound Beetle to a high-performance four-wheel disc brake setup, the standard 17mm or 19mm master cylinder often falls short of the hydraulic volume required to actuate larger calipers. The EMPI 22mm Buggy Master Cylinder with Billet Reservoir is the definitive solution for builders who demand a firm pedal and immediate stopping power. By utilizing a larger 22mm boreoriginally based on the heavy-duty Type 2 Bus architecturethis master cylinder displaces significantly more fluid with every stroke. This is absolutely critical for vehicles equipped with multi-piston calipers or rear disc conversions where the volume requirements of the wheel cylinders or calipers exceed what a stock Bug master can provide. Without this increased displacement, you often end up with a "mushy" pedal that travels too far before the pads actually bite the rotors. This unit eliminates that travel, providing a professional-grade braking feel that is essential for both technical trail maneuvers and high-speed safety.

Beyond its internal performance, this master cylinder kit is a masterpiece of space-saving engineering and durability. One of the biggest headaches in building a custom tube-chassis buggy or a narrow-beam street car is finding a secure, accessible location to mount a remote brake fluid reservoir. EMPI solves this by including a custom-machined billet aluminum reservoir that threads directly into the top of the master cylinder body. This eliminates the need for messy rubber grommets, blue plastic hoses, and remote mounting brackets that are prone to leaking or vibrating loose in harsh off-road environments. The reservoir features a high-quality O-ring seal and a knurled cap for easy maintenance. With four M10x1.0mm threaded ports, this master cylinder offers maximum plumbing versatility, allowing you to easily integrate dual-circuit safety lines, front and rear brake light switches, or even a line-lock system. When you choose this EMPI setup from Appletree Auto, you are investing in a component that is built to withstand the grit of the dunes while delivering the hydraulic precision of a modern performance vehicle.

FITMENT

• Dune Buggies & Sandrails: Ideal for all custom tube-frame chassis using VW-style pedal clusters.
• VW Beetle (Sedan & Convertible): 1950 through 1977 (Requires modification to the stock fluid line routing due to the direct-mount reservoir).
• VW Karmann Ghia: 1956 through 1974 (Fits custom performance applications with 4-wheel disc brakes).
• VW Type 2 Bus: 1950 through 1966 (Direct fit for early Bus owners looking for an upgraded reservoir system).
• VW Type 3 (Squareback, Fastback, Notchback): 1962 through 1973 (Custom performance applications).
• VW Thing (Type 181): 1973 through 1974.
• Custom Applications: Any vehicle utilizing a 2-bolt VW mounting flange pattern with 4-wheel disc brake conversions.

SPECS

• Bore Diameter: 22mm (Increased volume for disc brake conversions).
• Body Material: High-strength cast iron with a protective finish.
• Reservoir Material: CNC-Machined Billet Aluminum.
• Port Thread Size: M10 x 1.0mm (Standard VW brake line threading).
• Number of Ports: 4 (Allows for flexible plumbing and brake light switch integration).
• Mounting Style: 2-Bolt Flange (Standard Type 1 and Type 2 spacing).
• Reservoir Seal: High-temperature Viton O-ring for leak-free performance.
• Compatibility: Compatible with DOT 3, DOT 4, and DOT 5.1 brake fluids.
• Finish: Natural cast body with a polished aluminum reservoir cap.

PRO TIPS

1. The Golden Rule of Bench Bleeding

Before you ever bolt this 22mm master cylinder to your chassis, you must bench bleed the unit. Because of the larger bore and the internal piston design, air bubbles can become trapped in the rear of the cylinder if it is bled only on the car. Use a bench bleeding kit to loop the fluid from the output ports back into the billet reservoir. Slowly pump the piston by hand until every single micro-bubble is gone. If you skip this step, you might spend hours bleeding the lines at the wheels and still end up with a spongy pedal. Taking ten minutes on the workbench ensures that the core of your hydraulic system is solid from the very first pump.

2. Understanding Pedal Ratio and Pressure

It is important to remember that physics is a trade-off. By moving to a 22mm bore from a stock 19mm bore, you are increasing the volume of fluid moved (which is great for disc brakes), but you will also increase the amount of leg force required to generate the same line pressure. This is why it is called a "Buggy Master"it works best in lightweight vehicles or those with high-leverage pedal assemblies. If you find the pedal feels too "stiff" for your liking, check your pedal ratio. Most VW-based buggies have plenty of leverage, making this 22mm unit the perfect balance between a short, firm pedal stroke and powerful clamping force at the calipers.

3. Managing the Direct-Mount Reservoir

The billet reservoir is a huge advantage for space, but in a standard VW Beetle body, it sits very close to the body metal near the inspection plate. Always mock up your master cylinder with the reservoir installed before final-tightening your mounting bolts. In some tight street-car applications, you may need to slightly trim the sheet metal or use a 90-degree adapter if you are running custom hard lines. Additionally, always ensure the O-ring on the base of the billet reservoir is lubricated with a tiny amount of clean brake fluid before threading it into the cast body. This prevents the seal from "bunching" and ensures a vacuum-tight fit that won''t weep fluid over time.