7/8 Bore Tall Rectangular Master cylinder, Polished

OVERVIEW

Upgrade your stopping power and engine bay aesthetics with the EMPI 7/8 Bore Tall Rectangular Master Cylinder. Specifically engineered for high-performance applications, this master cylinder features a larger 7/8-inch bore size that provides the necessary fluid displacement required for heavy-duty braking systems, particularly those utilizing four-wheel disc brake conversions. While standard master cylinders might leave your pedal feeling soft or lacking the volume to fully engage multi-piston calipers, this unit delivers a firm, responsive pedal feel that inspires confidence whether you are navigating a steep sand dune or cruising the local strip. The polished finish isn''t just for show; it offers a durable layer of protection against the elements while ensuring your custom pedal assembly looks as good as it performs. This is a tall-style reservoir design, which means it holds a greater volume of brake fluid compared to shallow models, providing an extra margin of safety against fluid aeration and heat soak during aggressive driving sessions.

Designed to be the centerpiece of an aftermarket pedal cluster, this master cylinder is the go-to choice for sand rails, dune buggies, and custom air-cooled VW builds. It utilizes a vertical mounting configuration with holes spaced 2-1/4 inches apart, making it compatible with the vast majority of aftermarket pedal assemblies from brands like EMPI, Latest Rage, and CNC. The single 1/8-inch NPT outlet port offers a streamlined plumbing solution for simplified brake systems or can be split for multi-wheel configurations. Because this is an economy-line closeout item, it provides an incredible value for builders who demand professional-grade specifications without the premium price tag. Whether you are building a dedicated off-road beast or a show-quality street machine, the combination of a high-capacity reservoir and a precision-honed 7/8-inch bore makes this master cylinder an essential component for any serious brake system overhaul.

FITMENT

• Sand Rails & Dune Buggies: Universal fitment for most aftermarket floor-mount or hang-mount pedal kits.
• Baja Bugs: Ideal for custom builds using specialized pedal assemblies rather than stock floor pans.
• Manx Style Buggies: Fits perfectly in tight chassis spaces where a tall, narrow reservoir is preferred.
• Custom VW Drag Cars: Excellent for simplified braking systems requiring a high-pressure master cylinder.
• Note: Requires a 1/8-inch NPT adapter to connect to standard Volkswagen 10mm hard lines.

SPECS

• Bore Size: 7/8 inch (0.875").
• Reservoir Style: Tall Rectangular (Increased Fluid Capacity).
• Finish: High-Luster Polished Aluminum.
• Outlet Port: Single 1/8-inch NPT.
• Mounting Pattern: 2-1/4 inches center-to-center (Vertical 12 and 6 o''clock configuration).
• Fluid Compatibility: Compatible with DOT 3, DOT 4, and DOT 5.1 brake fluids.
• Material: Lightweight cast alloy body with precision-machined internals.
• Application Type: Optimized for 4-wheel disc brakes; also compatible with 2-wheel systems.

PRO TIPS

1. Bench Bleed Before Installation

Never install a new master cylinder without bench bleeding it first. Because this is a tall rectangular style, air bubbles can easily become trapped in the upper corners of the cylinder bore. Use a bench bleeding kit to cycle fluid through the unit until every trace of air is gone. If you skip this step, you may find it nearly impossible to get a firm pedal later, as the air trapped in the master cylinder will compress and prevent the rest of the system from reaching full pressure. Always use fresh fluid from a sealed container to avoid moisture contamination.

2. Selecting the Correct NPT Adapter

Since this master cylinder features a 1/8-inch NPT outlet, it will not directly accept a standard VW M10x1.0 brake line fitting. You must use a 1/8-inch NPT to M10x1.0 adapter (or the appropriate size for your specific brake lines). When installing the NPT fitting, use a small amount of Teflon tape or thread sealant on the NPT side only, ensuring no sealant enters the fluid path. Be careful not to over-tighten, as NPT threads are tapered and can crack the aluminum housing if forced too deep.

3. Understanding the 7/8 Bore Advantage

The 7/8-inch bore is larger than the standard 5/8 or 3/4-inch bores often found on smaller buggies. This means that for every inch of pedal stroke, you are moving a larger volume of fluid. This is ideal if you are running large calipers with multiple pistons, as they require more volume to move the pads. However, be aware that a larger bore requires slightly more physical leg effort to create the same line pressure as a smaller bore. This trade-off results in a "shorter" and "firmer" pedal feel, which is preferred by performance drivers for better modulation and control.