The Essential 1″ Bore Upgrade for Mazda MX-5 Miata (NA & NB)
The legendary Mazda MX-5 (Miata) platforms (NA and NB) deserve a modern braking feel. The factory brake pedal is often described as soft or spongy, especially when using upgraded calipers. The HFM.Parts High Volume Master Cylinder is the definitive solution, engineered to increase the bore diameter from the original 7/8″ (22.23mm) to a high-performance 1″ (25.4mm).
This increase in fluid volume directly translates to superior pedal feel. You will experience a significant reduction in brake pedal travel and a consistent, firmer pedal response, making your braking more predictable and confident whether you are commuting or hitting the track. This master cylinder is suitable for both standard OEM calipers and multi-piston big brake kit applications.
Key Advantages & Performance Features
This high-volume unit is engineered for the NA/NB platform:
- 1″ (25.4mm) Bore Upgrade: Provides substantially increased fluid volume and reduced pedal travel over the factory 7/8″ (22.23mm) bore.
- Universal LHD/RHD Compatibility: Designed for easy fitment on both Left-Hand Drive and Right-Hand Drive models, with a swappable fluid sensor and included grub screws to safely block unused ports.
- Suitable for All Calipers: Excellent upgrade for those retaining OEM calipers or installing larger multi-piston caliper kits.
- Corrosion-Proof Geomet® Coating: Features a durable, premium finish for long-term heat and environmental resistance.
Technical Specifications Snapshot
- Piston Bore: 1″ (25.4mm) (Upgraded from 7/8″ / 22.23mm OEM)
- Fitment: Universal LHD and RHD (Sensor is swappable)
- Included: 3x Grub Screws and 2x Copper Washers for install flexibility.
- Coating: Geomet® Finish
- Suitable for Stock & Multi-Piston Calipers
- Improved Brake Pedal Responsiveness
- Increased Brake Fluid Volume