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
What's Included
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1× Brake Master Cylinder
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3× Grub Screw
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2× Copper Washer
Customer Installs
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Our compatibility list is based on OEM specifications. Variations may exist due to vehicle sub-models or other factors — verify fitment before purchasing.
Yes, you can! You can easily squeeze the two tabs on either side of the sensor, slide the sensor out, and switch it to the other side.
This application is ideal for enhancing your braking performance by reducing any spongy feeling in the pedal and increasing its firmness. You will experience improved pedal responsiveness with reduced travel.
We have included Tapered Grub Screw’s so that this model can be applied to both ABS and NON-ABS vehicles. Simply block off any unused ports using the included grub srews.
Yes, they are different. To use our BMC with ABS, you will need to swap the ABS booster for a non-ABS one.
Our Story
We weren't always HFM.Parts; we were Holford Motors. Our brand's identity was forged not in an office, but on the local circuits in the high-stress world of competitive drifting. Our ultimate testbed was our Nissan S14 Drift car, driven by champion Luke Fink. Pushing that car to its limits exposed a crucial truth: achieving genuine, repeatable performance meant relying on components that simply weren't available affordably on the market.
The HFM.Parts brand was born
We made the commitment to design and manufacture the uncompromising, high-quality performance parts that we, as competitive racers, demanded ourselves. Every component you see is a solution conceived, tested, and proven by us. When you choose HFM.Parts, you are investing in components engineered by racers, for racers, ensuring your vehicle delivers its maximum performance potential.
Modifying vehicles is a specialist task and requires the knowledge and experience of competent
individuals to
be conducted safely.
We recommend this product be installed by a competent person. Instructions are given with every
order
where
available, however, If you would like a copy prior to ordering, you're welcome to contact us
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