Project Mu Brake Fluid

Project Mu G-Four 335: Race-Engineered Brake Fluid

Project Mu has built its reputation since 1988 as one of the world's foremost brake specialists. Fusing motorsport DNA, Japanese technology, and over 30 years of racing experience, Project Mu has formulated braking solutions accepted worldwide. That same philosophy extends beyond brake pads and rotors — it flows directly into their brake fluid lineup.

The G-Four 335: Engineering That Goes Beyond DOT Standards

Project Mu's flagship brake fluid offering is the G-Four 335, and it stands apart in a crowded market for one critical reason: raw thermal performance. The G-Four 335 is capable of withstanding temperatures as high as 335 degrees Celsius (635 degrees Fahrenheit) at its dry boiling point. Its wet boiling point comes in at 430°F (221°C). These figures place it well beyond what most drivers will ever encounter, whether on the street or the circuit.

The G-Four 335 is a 100% synthetic glycol fluid that meets and even exceeds DOT-5 requirements. It is recommended for competition use and is equally excellent for street use. This dual-purpose capability is a hallmark of Project Mu's engineering approach — products born from motorsport that translate seamlessly to road cars.

The Color-Change Visual Indicator: A Practical Innovation

One of the most distinctive features of the G-Four 335 has nothing to do with raw numbers — it's a clever visual cue built into the fluid itself. The fluid features a unique green color that changes to crystal clear when it approaches its boiling point, serving as a visual indicator for fluid replacement.

The green color allows the user to see vapor bubbles clearly during bleeding, and the color-changing feature makes it easy to identify exhausted fluid (which turns clear) versus fresh fluid (which remains green). This means track day enthusiasts can have a safer outing after bleeding trapped vapor, and service technicians can be assured that brakes are truly bled properly.

Race-Proven, Street-Ready

Founded in 1988, Project Mu quickly gained a reputation for innovation, aggressive R&D, and uncompromising safety standards, becoming a brake supplier of choice for countless teams in Super GT, Super Taikyu, Formula Drift, WRC, and more. All Project Mu products are manufactured in the Project Mu plant in Japan to strict ISO 9001 quality requirements. The G-Four 335 reflects that same uncompromising standard in fluid form.

When upgrading your brake system, you should always improve the quality of your fluid to match the increased demands on your braking system. For anyone running upgraded pads, larger calipers, or simply spending time on a track, the G-Four 335 is the logical complement to a serious brake setup.

Explore the full Project Mu brand catalog or browse all brake fluids to find the right fluid for your application.