MPA Electrical NM55638 Brake Master Cylinder

Brake Master Cylinder for Kia Optima and Hyundai Sonata

Restore consistent brake pedal response with this MPA Electrical brake master cylinder, part number NM55638. Built as a standard replacement for vehicles with front disc brakes, it is engineered for direct hydraulic performance on select Kia Optima and Hyundai Sonata applications.

MPA Electrical’s New with front disc brakes product line focuses on replacement brake hydraulics that are tested against OE specifications using controlled validation processes. This NM55638 master cylinder is a practical choice when replacing a worn or leaking unit on a 2016-2020 Kia Optima or a 2015-2019 Hyundai Sonata.

Key Features

• Brake master cylinder for brake hydraulic service
• Standard replacement grade
• Aluminum master cylinder body with plastic reservoir
• Reservoir included with cap and gasket/seal included
• 0.875 in. bore diameter
• 2 mounting holes with 0.334 in. mounting hole diameter
• Uses DOT 3 or DOT 4 brake fluid
• New condition, with front disc brakes application
• MPA Electrical NM55638

Detailed Description

The MPA Electrical NM55638 brake master cylinder is built to restore hydraulic pressure in the braking system by replacing a worn original unit with a standard replacement design. The aluminum housing, included reservoir, cap, and seal help support a complete service replacement, while the 0.875-inch bore diameter matches the specified OE-style application requirements. This part is intended for 2016-2020 Kia Optima and 2015-2019 Hyundai Sonata models with front disc brakes, making it a focused solution for common brake pedal and hydraulic complaints.

This part cross-references 58510C1200 for the same application.

What It Helps Fix

• Low or inconsistent brake pedal feel
• External brake fluid leakage at the master cylinder
• Loss of hydraulic pressure in the brake system
• Brake pedal travel that feels excessive or soft
• Brake performance issues caused by a worn master cylinder bore or seals

Installation Notes and Tips

Verify vehicle fitment by year, make, model, and front disc brake configuration before installation. Bench bleeding the master cylinder before final installation helps reduce trapped air in the hydraulic system. Use clean DOT 3 or DOT 4 brake fluid only, and inspect the brake lines, booster interface, and reservoir connections for wear or contamination during service. Mounting hardware, brake booster, push rod, sensor, and brake pressure switch are not included.

Quality Assurance

MPA Electrical tests each brake master cylinder against OE specifications using proprietary processes and strict validation protocols to support consistent braking performance after installation. Part number NM55638 is a new replacement brake master cylinder for select Kia Optima and Hyundai Sonata applications.