Genuine Mazda Clutch Master Cylinder With Reservoir – RHD • B425-41-400

Genuine Mazda B425-41-400 Clutch Master Cylinder With Reservoir

Replacement Genuine Mazda clutch master cylinder for right-hand-drive Mazda MX-5 Mk1 NA, Mk2 NB and Mk2.5 NB-FL manual-transmission models from 1989 to 2005 listed in the compatibility table.

The clutch master cylinder converts clutch-pedal movement into hydraulic pressure. When the pedal is pressed, fluid is displaced through the clutch pipe and flexible hose to operate the slave cylinder, allowing the clutch to disengage from the engine.

The cylinder is mounted to the vehicle bulkhead in the engine bay and connects mechanically to the clutch pedal inside the cabin. There is typically one clutch master cylinder fitted per vehicle. This listing is for one Genuine Mazda cylinder with its fluid reservoir.

Internal seal wear, corrosion or fluid leakage can cause a soft or sinking clutch pedal, incomplete clutch disengagement, difficulty selecting gears, inconsistent pedal operation or visible hydraulic-fluid loss around the cylinder and bulkhead.

• Part type: Clutch master cylinder with fluid reservoir
• Primary use: Generates hydraulic pressure to operate the clutch slave cylinder
• Location: Engine-bay bulkhead, connected to the clutch pedal
• Position: Clutch hydraulic control system
• Quantity per vehicle: 1
• Quantity supplied: 1 clutch master cylinder with reservoir
• Brand: Genuine Mazda
• Part No.: B425-41-400
• Also referenced as: B42541400
• Fitment note: For confirmed right-hand-drive Mazda MX-5 Mk1, Mk2 and Mk2.5 manual-transmission applications only

Fitment advice: This cylinder is specifically intended for right-hand-drive vehicles fitted with a manual transmission. It is not suitable for left-hand-drive MX-5 models or automatic-transmission vehicles. For imported, modified or previously repaired cars, matching the original cylinder layout, pipe connection, pedal arrangement and part number is recommended.

Other items to consider: When changing this part, you may also want to consider purchasing the clutch slave cylinder, flexible clutch hose, hydraulic-pipe sealing components and fresh brake/clutch fluid. Inspect the rigid hydraulic pipe, pedal clevis and associated mounting hardware for wear, corrosion or fluid contamination.

Useful tools / consumables: Flare-nut spanners, socket set, long-reach extensions, pliers, fluid-catching container, protective gloves, eye protection, brake cleaner, fresh manufacturer-specified brake/clutch fluid and clutch-bleeding equipment.

Difficulty guide: DIY Difficulty: Moderate. Installation requires access from the engine bay and clutch-pedal area, careful disconnection of the hydraulic pipe and complete bleeding of the clutch system. Hydraulic fluid can damage paint, so spills should be cleaned immediately.

Why Genuine Mazda? Genuine Mazda clutch hydraulic components are designed to match the original cylinder bore, pedal linkage, bulkhead mounting points and hydraulic-pipe connections. Correct internal specification and seal quality help maintain consistent hydraulic pressure, clutch release operation and compatibility with the original slave cylinder and clutch system.

What’s in the box: One Genuine Mazda clutch master cylinder with fluid reservoir, part number B425-41-400.

Installation notes: Protect painted surfaces before disconnecting the hydraulic pipe. Remove the pedal clevis connection and cylinder mounting hardware, then install the replacement cylinder in the original orientation. Connect the hydraulic pipe without cross-threading the fitting, fill the reservoir with the specified fluid and bleed the system until the pedal is firm and free from trapped air. Check all connections for leaks and confirm complete clutch disengagement before driving.