ProX Front Master Cylinder Rebuild Kit 37.910002 — Honda / Yamaha / Kawasaki / Suzuki 1993-2026

Product Description

Restore crisp, rock-solid braking performance and eliminate a spongy front lever with the ProX Front Master Cylinder Rebuild Kit. Over time, exposure to moisture, extreme heat, and deteriorating brake fluid deforms the internal rubber cups and corrodes the return piston inside your factory perch. This results in pressure loss, fluid bypass, or a front brake lever that slowly creeps back to the bars. This premium rebuild package updates your internal components to re-establish instant hydraulic pressure accuracy.

Every kit is sourced from world-class tier-one manufacturers and engineered to meet or strictly exceed OEM performance specifications. Packed with a precision-machined replacement piston, high-tension return spring, fresh fluid sealing cups, a new copper crush washer set, and an external rubber dust boot, this kit completely overhauls the wear components. Upgrading with ProX ensures factory-level feel and consistent stopping power down the longest racing motos.

Top Features: ProX Master Cylinder Rebuild Kit
o Comprehensive front brake master cylinder kit including replacement piston, return spring, sealing cups, and hardware.
o Precision-molded rubber cup seals restore a leak-free hydraulic fitment match to prevent inner pressure drop.
o Manufactured to exact OEM dimensions for seamless drop-in placement inside factory front Nissin perches.
o Includes a fresh external rubber dust boot to aggressively lock out moisture, pressure-washer spray, and track silt.

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Frequently Asked Questions

Q: Does this kit include the front brake lever or the outer fluid reservoir body?
A: No, this kit includes only the internal replacement piston assembly, springs, snap ring, washers, and seals required to rebuild the inside of your existing factory assembly.

Q: Will this rebuild kit function correctly if I have an aftermarket brake master cylinder?
A: This kit is strictly designed to match factory OEM assemblies (typically original Nissin units). It will not fit aftermarket hydraulic setups like Brembo or Magura conversion master cylinders.

Q: What type of brake fluid should be used when completing this rebuild?
A: Always use fresh, high-quality fluid from a sealed container matching the specific rating stamped on your reservoir cap—typically high-temperature DOT 4 fluid for modern off-road machines.

Expert Pro-Tip: When sliding the new rubber cup seals onto the replacement piston assembly, never install them bone-dry or use chemical sprays that can swell the rubber. Instead, coat the new piston and seals liberally with fresh, clean DOT 4 brake fluid. This acts as a safe lubricant, allowing the components to slide effortlessly into the cylinder bore without tearing or folding the critical seal edges during installation.

Recommended Pairings:
o Motorcycle Chemicals Performance Parts
o Motorcycle Tools Performance Parts
o Honda CRF250R Performance Parts & Upgrades

At Moto-House MX, we carry the best brands in motocross and off-road performance. Our team has over 40 years of experience helping riders get more out of their bikes. Every order ships fast from our Central Florida location.

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