HomeBrake > Hardware, Fasteners and FittingsMPA Electrical B3871 Power Brake Booster
Part #: B3871

MPA Electrical B3871 Power Brake Booster

Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
$335.90Free Shipping
Free ShippingNo Cost to Continental U.S.
Free Returns*Wrong fit? No cost
60-Day ReturnsMoney back guarantee
*Free return shipping only qualifies if our fitment verification tool is used.
In Stock · Ready To Ship Most orders ship same-day if ordered before 1pm CST.
OE Direct Replacement — Bolt-on fit, no modifications needed
Easy Returns — Return within 60 days for a full refund
Fast Shipping — Most orders ship same business day before 1pm CST

Remanufactured Vacuum Brake Booster

MPA Electrical B3871 is a remanufactured vacuum power brake booster built for drivers who need consistent brake assist and a firm, predictable pedal feel. This standard replacement unit is engineered for direct service on compatible applications, including Toyota and Lexus brake systems that use a vacuum booster without a master cylinder.

The MPA Electrical brake booster line focuses on restored vacuum sealing, dependable pressure transfer, and end-of-line testing for each unit. B3871 follows that approach with treated replacement components and a metal housing for service-ready durability.

Key Features

  • Remanufactured vacuum power brake booster
  • Standard replacement brake service grade
  • 10.56 in. diaphragm diameter, 268.22 mm
  • Metal housing construction
  • 2 mounting studs with 8 x 1.25 mm master cylinder stud thread size
  • Master cylinder not included
  • Brake pedal rod extension not included
  • Gasket or seal not included
  • Mounting bracket not included
  • Front seal not included

Product Details

MPA Electrical B3871 is a reman Vac Pwr Brake Booster w/o Master Cyl designed for vacuum-assisted braking systems that require reliable assist with reduced pedal effort. The unit is tested at the end of production using proprietary equipment to verify performance before release. For shoppers searching for a brake booster for Toyota or Lexus applications, this part number is a direct reference point for the correct vacuum booster configuration.

This part cross-references Monroe Shocks & Struts (e.g., 172286) for the same application.

Common Brake Issues It Can Address

  • Hard brake pedal feel
  • Reduced brake assist during stopping
  • Vacuum booster leakage
  • Inconsistent pedal response
  • Brake system performance loss from a worn booster

Installation Notes

Verify vacuum booster type, diaphragm diameter, mounting stud count, and master cylinder stud thread size before installation. Because the master cylinder is not included, transfer or replace the master cylinder separately as required by the vehicle application. Confirm pedal rod length, firewall fitment, and vacuum hose condition during service. For Toyota and Lexus brake booster replacement jobs, match the original booster configuration to the vehicle’s brake system layout before installation.

Quality Assurance

MPA Electrical remanufactures this booster with specially treated replacement components and tests every unit at the end of the line to confirm braking performance and vacuum seal integrity. Part number B3871 is built to standard replacement expectations for service work on compatible vacuum brake systems.

BrandMPA Electrical
Part NumberB3871
Brake Service GradeStandard replacement
Booster TypeVacuum
Brake Pedal Rod Extension IncludedNo
Master Cylinder IncludedNo
Gasket Or Seal IncludedNo
Housing MaterialMetal
Diaphragm Diameter10.56
Diaphragm Diameter268.22
Mounting Bracket IncludedNo
Front Seal IncludedNo
Master Cylinder Stud Thread Size (mm)8 x 1.25
Mounting Stud Quantity2
Product ConditionRemanufactured

This part fits 0 vehicles. Search below:

YearMakeModelPositionNotes

* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.

This part directly replaces or is cross-referenced with the following part numbers:

8971779740

Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.