MPA Electrical M55280 Brake Master Cylinder

Brake Master Cylinder for Audi and Volkswagen

Restore consistent brake pedal response with this remanufactured brake master cylinder from MPA Electrical. Built for vehicles with front disc brakes, this standard replacement uses a 1-inch bore, aluminum construction, and DOT 4 fluid compatibility for direct hydraulic system service.

MPA Electrical remanufactures brake master cylinders using OE sample data and testing protocols that verify performance against OE specifications before release. Part number M55280 is a fitment-based replacement for select Audi A8 Quattro, S8, S4, A4, A4 Quattro, A6, A6 Quattro, A8, and Volkswagen Passat applications.

Key Features

• Remanufactured brake master cylinder
• 1-inch master cylinder bore diameter
• Aluminum master cylinder body
• Standard replacement grade
• Gasket or seal included
• DOT 4 fluid type
• Two mounting holes with 0.85-inch mounting hole diameter
• Configured for vehicles with front disc brakes
• Part number M55280

Detailed Description

This brake master cylinder is engineered for hydraulic brake system restoration on Audi and Volkswagen models that use front disc brakes. It is a remanufactured unit with a 1-inch bore, aluminum housing, and seal included, making it a direct service part for maintaining pedal feel and brake pressure delivery. MPA Electrical tests each unit against OE specifications to support consistent braking performance out of the box. This part cross-references 4D0611021A for the same application.

What It Helps Fix

• Low or inconsistent brake pedal response
• Internal hydraulic leakage in the master cylinder
• Brake fluid bypass that reduces braking pressure
• Soft or sinking pedal feel
• Brake system performance loss on front disc brake vehicles

Installation Notes and Tips

• Verify vehicle fitment by year, make, model, and front disc brake configuration before installation.
• Bench bleed the master cylinder before connecting brake lines.
• Use clean DOT 4 brake fluid and flush contaminated fluid from the system.
• Inspect brake lines, booster interface, and mounting surfaces for wear or corrosion during service.
• Mounting hardware, reservoir, cap, push rod, brake booster, sensor, and pressure switch are not included.

Quality Assurance

MPA Electrical remanufactures this master cylinder using OE sample references and controlled testing procedures to confirm it meets OE-based specifications. That process supports reliable hydraulic performance for Audi A8 Quattro, Audi S8, Audi S4, Audi A4, Audi A4 Quattro, Audi A6, Audi A6 Quattro, Audi A8, and Volkswagen Passat brake service.