MPA Electrical B3728 Power Brake Booster

Overview

This remanufactured vacuum power brake booster is built for drivers who need consistent braking assist and a firm, predictable pedal feel. It is a standard replacement unit for select Scion applications and is identified by part number B3728.

Compatible with 2005-2006 Scion xA and 2004-2006 Scion xB, this booster is engineered to restore vacuum-assisted braking performance with minimal pedal effort. The metal housing, 9.72-inch diaphragm diameter, and 8 x 1.25 mm master cylinder stud thread size support proper fitment for the intended applications.

Key Features

• Vacuum brake booster design for power-assisted braking
• Remanufactured standard replacement unit
• Metal housing construction
• 9.72-inch diaphragm diameter
• Two mounting studs for installation
• Part number B3728 for identification and ordering

Detailed Description

MPA Electrical remanufactures this power brake booster to deliver reliable vacuum assist and improved pedal response in the specified Scion xA and Scion xB applications. According to the manufacturer, the unit uses new replacement and specially treated components to help maintain vacuum sealing and pressure transfer, and each unit is end-of-line tested before release. This part cross-references Toyota numbers 4461052340 and 4461052341 for the same application.

The B3728 brake booster is a practical choice when the original vacuum booster shows reduced assist, internal leakage, or inconsistent pedal feel. It is supplied without a master cylinder, pedal rod extension, gasket, seal, or mounting bracket, so the existing vehicle-specific components must be evaluated during service.

What It Helps Solve

• Hard brake pedal feel caused by weak vacuum assist
• Reduced braking response from a leaking booster diaphragm or seal
• Inconsistent pedal effort during normal stopping
• Brake assist loss related to booster wear or contamination
• Replacement needs for remanufactured brake booster service

Installation Notes and Tips

Verify master cylinder compatibility before installation, since the master cylinder is not included. Confirm the 8 x 1.25 mm stud thread size and inspect the existing mounting points, vacuum supply, and pedal linkage condition before reassembly. For Scion xA and Scion xB brake service, compare the removed unit to B3728 to confirm the correct booster configuration.

Quality Assurance

MPA Electrical subjects each unit to 100% end-of-line testing using proprietary equipment. The remanufactured construction and tested vacuum booster design support consistent braking assist for the listed applications.