Master Cylinder .625in Bore Girling Style

OVERVIEW

When it comes to precision braking and clutch actuation in the air-cooled world, the Wilwood .625-inch Bore Girling Style Master Cylinder stands as the gold standard for performance and reliability. Engineered by the industry leaders at Wilwood, this master cylinder is specifically designed to meet the rigorous demands of lightweight off-road vehicles, custom sand rails, and high-performance VW Beetle builds. The .625-inch (5/8-inch) bore size is the ideal choice for builders looking to achieve a softer pedal feel with increased travel, providing superior modulation and control over hydraulic clutch systems or small-caliper brake setups. Constructed from high-pressure die-cast aluminum and finished with a sleek, durable black anodized coating, this unit doesn''t just perform flawlesslyit looks the part in any professional engine bay or chassis setup.

The Girling-style design is a favorite among VW enthusiasts because of its compact footprint and integral reservoir, which eliminates the need for external plumbing and remote tanks, saving precious space and reducing potential leak points. Whether you are navigating a technical trail in a Meyers Manx, launching off a dune in a high-horsepower sand rail, or upgrading the clutch feel on your street-driven Baja Bug, this Wilwood master cylinder provides the consistent pressure and quick recovery you need. It is a robust upgrade over stock-style components, offering a 1.25-inch stroke that ensures full engagement and disengagement of your hydraulic components. When you choose Wilwood from Appletree Automotive, you are investing in a component that has been track-tested and desert-proven to withstand the harshest environments the air-cooled world can throw at it.

FITMENT

• VW Beetle (All Years): Custom hydraulic clutch conversions and performance brake upgrades.
• VW Karmann Ghia: Ideal for specialized racing or performance pedal assemblies.
• Dune Buggies: Perfect for Meyers Manx, EMPI Imp, and other fiberglass body kits.
• Sand Rails & Off-Road Frames: Fits Chenowth, Berrien, and custom tube chassis utilizing Girling-style mounts.
• Baja Bugs: Excellent for heavy-duty clutch actuation or rear turning brake setups.
• Universal Racing Applications: Compatible with any pedal assembly designed for a standard 2.25-inch center-to-center flange mount.

SPECS

• Bore Size: 0.625 inch (5/8").
• Stroke Length: 1.25 inches.
• Material: High-strength die-cast aluminum.
• Finish: Black Anodized for superior corrosion resistance.
• Reservoir Type: Integral (built-in) with threaded cap.
• Mounting Style: Girling-style 2-bolt flange.
• Mounting Hole Center-to-Center: 2.25 inches.
• Outlet Port Thread: 3/8-24 UNF.
• Piston Material: High-grade aluminum with specialized seals.

PRO TIPS

1. Always Bench Bleed Before Installation

Never install a master cylinder dry. To ensure a firm pedal and prevent trapped air from entering your hard lines, you must bench bleed the Wilwood unit. Secure the cylinder in a vise, fill the reservoir with fresh DOT 3 or 4 fluid, and use a bleed kit to loop the fluid from the outlet port back into the reservoir. Slowly pump the piston until all air bubbles vanish. This process saves hours of frustration and ensures that your hydraulic system starts with a solid foundation of pressure.

2. Match the Bore Size to Your Application

Choosing the correct bore size is critical for the mechanical advantage of your pedal assembly. The .625-inch bore is specifically designed to provide more hydraulic pressure with less physical effort compared to larger bore cylinders. If you find your clutch is too stiff or your turning brakes require too much leg strength, swapping to this 5/8-inch bore will increase your leverage. However, keep in mind that a smaller bore requires more pedal travel to move the same volume of fluid, so ensure your pedal has enough throw to fully actuate the slave cylinder or calipers.

3. Check for Pushrod Geometry and Clearance

When installing this in a custom VW floor pedal or a hanging pedal assembly, ensure your pushrod is perfectly centered and aligned with the master cylinder piston. If the pushrod enters at an angle, it will cause premature wear on the internal seals and lead to leaks. Additionally, always leave a small amount of "free play" (about 1/16 of an inch) between the pushrod and the piston when the pedal is at rest. This ensures the compensating port inside the master cylinder can open fully, allowing fluid to return to the reservoir and preventing your brakes or clutch from "pumping up" and dragging during operation.