Shimano Hydraulic Mineral Oil for Disc Brake - 100ml

Why Does Shimano Hydraulic Disc Brake Fluid Have to Be Mineral Oil?

Shimano hydraulic disc brakes are designed exclusively for use with mineral oil, and this is the genuine Shimano-spec fluid in a 100ml bottle. Unlike DOT fluid, which is used in many competing brake systems, Shimano mineral oil is non-hygroscopic, meaning it does not absorb moisture from the atmosphere over time. This matters because DOT fluid that absorbs water will lower the boiling point of the hydraulic system over time, eventually leading to brake fade under hard use. Shimano's mineral oil maintains its boiling point characteristics across its service life, reducing the urgency of annual fluid changes that DOT systems require to prevent moisture contamination from degrading performance.

Beyond performance, mineral oil is significantly less damaging to painted frame finishes, rubber seals, and skin compared to DOT fluid, which is corrosive and requires careful handling. If a small amount of Shimano mineral oil contacts your frame or hands during a bleed, it will not cause damage. It is also considered more environmentally friendly to dispose of. This 100ml bottle is the correct size for a single brake bleed with enough left over for minor top-offs. Using any fluid other than Shimano-specified mineral oil in a Shimano hydraulic brake system will damage internal seals and void serviceability. Never use DOT fluid in a Shimano brake system under any circumstances. For complete brake bleeds or topping off, this is the only fluid to use.