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Dorman M630918 Brake Master CylinderOE Quality 60-Day Returns
Part #: M630918

Dorman M630918 Brake Master Cylinder

113 vehicles fit this part
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OE Direct Replacement — Bolt-on fit, no modifications needed
Fitment: BMW, 125i, 230i, 230i xDrive, 328d, 328d xDrive, 328i, 328i GT xDrive, 328i xDrive, 330e, 330i, 330i GT xDrive, 330i xDrive, 335i, 335i GT xDrive, 335i xDrive, 340i, 340i GT xDrive, 340i xDrive, 428i, 428i Gran Coupe, 428i xDrive, 428i xDrive Gran Coupe, 430i, 430i Gran Coupe, 430i xDrive, 430i xDrive Gran Coupe, 435i, 435i Gran Coupe, 435i xDrive, 435i xDrive Gran Coupe, 440i, 440i Gran Coupe, 440i xDrive, 440i xDrive Gran Coupe, 520i, 530e, 530e xDrive, 530i, 530i xDrive, 540i, 540i xDrive, 740e xDrive, 750i, 750i xDrive, 750Li, 750Li xDrive, ActiveHybrid 3, M135i, M140i, M2, M235i, M235i xDrive, M240i, and M240i xDrive
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Brake Master Cylinder for BMW Applications

Dorman M630918 is a brake master cylinder built for specific BMW years, makes, and models. It uses new, high-quality materials and is precision-engineered to match the original unit’s design, function, and performance.

  • Brake master cylinder for select BMW 125i, 328i, 330i, 340i, 430i, 440i, 530i, 540i, 750i, M2, M235i, and M240i applications
  • 1-inch bore diameter for OE-style hydraulic operation
  • Cast iron master cylinder body for durable construction
  • Two outlets with M12x1.0 rearward outlet size and M12x1.0 secondary outlet thread diameter
  • Removable reservoir type; reservoir and sensor not included
  • Part number M630918 for direct reference and catalog lookup

Detailed Product Overview

This brake master cylinder is designed for BMW brake hydraulic systems that require a 1-inch bore and a two-outlet layout. Dorman M630918 is a direct replacement-style component for vehicles such as the BMW 328i, 330i, 430i, 530i, 540i, M2, and M240i, helping restore consistent brake pedal response and hydraulic pressure delivery. This part cross-references Raybestos Brakes MC391505 for the same application.

Built from cast iron and supplied as the master cylinder only, this unit is intended for vehicles using a removable reservoir design. The M630918 part number is also useful when verifying interchange references during brake system service.

What This Part Helps Address

  • Soft or inconsistent brake pedal feel
  • Internal master cylinder leakage
  • Loss of hydraulic pressure in the brake system
  • Brake fluid bypass inside the master cylinder
  • Brake warning symptoms tied to master cylinder wear

Installation Notes and Tips

Confirm bore size, outlet thread size, and reservoir style before installation. This master cylinder does not include mounting hardware, reservoir, or sensor, so reuse or source the required related components as needed. After installation, bleed the brake system thoroughly to remove air and verify proper pedal firmness. Always match the vehicle’s brake hydraulic configuration to the listed fitment before service.

Quality Assurance

Dorman engineers this replacement master cylinder to match the original part’s design and performance on the listed BMW applications. New materials and OE-style construction support dependable brake system service for the covered vehicles.

  • Fits 2017-2019 BMW 230i
  • Fits 2017-2019 BMW 230i xDrive
  • Fits 2017-2019 BMW 340i GT xDrive
  • Fits 2018-2019 BMW 430i
  • Fits 2018-2019 BMW 430i Gran Coupe
  • Fits 2018-2019 BMW 430i xDrive
  • Fits 2018-2019 BMW 430i xDrive Gran Coupe
  • Fits 2018-2019 BMW 440i
  • Fits 2018-2019 BMW 440i Gran Coupe
  • Fits 2018-2019 BMW 440i xDrive
  • Fits 2018-2019 BMW 440i xDrive Gran Coupe
  • Fits 2019 BMW 520i
  • Fits 2019 BMW 530e
  • Fits 2019 BMW 530e xDrive
  • Fits 2019 BMW 530i
  • Fits 2019 BMW 530i xDrive
  • Fits 2019 BMW 540i
  • Fits 2019 BMW 540i xDrive
  • Fits 2019 BMW 740e xDrive
  • Fits 2019 BMW 750i
  • Fits 2019 BMW 750i xDrive
  • Fits 2019 BMW 750Li
  • Fits 2019 BMW 750Li xDrive
  • Fits 2017-2019 BMW M140i
  • Fits 2016-2019 BMW M2
  • Fits 2017-2019 BMW M240i
  • Fits 2017-2019 BMW M240i xDrive
  • Fits 2014-2018 BMW 328d
  • Fits 2014-2018 BMW 328d xDrive
  • Fits 2016-2018 BMW 330e
  • Fits 2016-2018 BMW 330i
  • Fits 2017-2018 BMW 330i GT xDrive
  • Fits 2017-2018 BMW 330i xDrive
  • Fits 2016-2018 BMW 340i
  • Fits 2016-2018 BMW 340i xDrive
  • Fits 2014-2016 BMW 328i
  • Fits 2014-2016 BMW 328i GT xDrive
  • Fits 2014-2016 BMW 328i xDrive
  • Fits 2014-2016 BMW 335i GT xDrive
  • Fits 2013-2016 BMW M135i
  • Fits 2014-2016 BMW M235i
  • Fits 2015-2016 BMW M235i xDrive
  • Fits 2014-2015 BMW 335i
  • Fits 2014-2015 BMW 335i xDrive
  • Fits 2015 BMW 428i
  • Fits 2015 BMW 428i Gran Coupe
  • Fits 2015 BMW 428i xDrive
  • Fits 2015 BMW 428i xDrive Gran Coupe
  • Fits 2015 BMW 435i
  • Fits 2015 BMW 435i Gran Coupe
  • Fits 2015 BMW 435i xDrive
  • Fits 2015 BMW 435i xDrive Gran Coupe
  • Fits 2013-2015 BMW ActiveHybrid 3
  • Fits 2013 BMW 125i
BrandDorman
Part NumberM630918
Mounting Hardware IncludedNo
Master Cylinder Bore Diameter1
Master Cylinder MaterialCast iron
Reservoir IncludedNo
Sensor IncludedNo
Number of Outlets2
Package ContentsMaster cylinder
Rearward Outlet SizeM12x1.0
Reservoir TypeRemovable
Secondary Outlet Thread DiameterM12x1.0

This part fits 113 vehicles. Search below:

YearMakeModelPositionNotes
2019BMW230iN/A
2019BMW230i xDriveN/A
2019BMW340i GT xDriveN/A
2019BMW430iN/A
2019BMW430i Gran CoupeN/A
2019BMW430i xDriveN/A
2019BMW430i xDrive Gran CoupeN/A
2019BMW440iN/A
2019BMW440i Gran CoupeN/A
2019BMW440i xDriveN/A
2019BMW440i xDrive Gran CoupeN/A
2019BMW520iN/A
2019BMW530eN/A
2019BMW530e xDriveN/A
2019BMW530iN/A
2019BMW530i xDriveN/A
2019BMW540iN/A
2019BMW540i xDriveN/A
2019BMW740e xDriveN/A
2019BMW750iN/A
2019BMW750i xDriveN/A
2019BMW750LiN/A
2019BMW750Li xDriveN/A
2019BMWM140iN/A
2019BMWM2N/A
2019BMWM240iN/A
2019BMWM240i xDriveN/A
2018BMW230iN/A
2018BMW230i xDriveN/A
2018BMW328dN/A
2018BMW328d xDriveN/A
2018BMW330eN/A
2018BMW330iN/A
2018BMW330i GT xDriveN/A
2018BMW330i xDriveN/A
2018BMW340iN/A
2018BMW340i GT xDriveN/A
2018BMW340i xDriveN/A
2018BMW430iN/A
2018BMW430i Gran CoupeN/A
2018BMW430i xDriveN/A
2018BMW430i xDrive Gran CoupeN/A
2018BMW440iN/A
2018BMW440i Gran CoupeN/A
2018BMW440i xDriveN/A
2018BMW440i xDrive Gran CoupeN/A
2018BMWM140iN/A
2018BMWM2N/A
2018BMWM240iN/A
2018BMWM240i xDriveN/A
2017BMW230iN/A
2017BMW230i xDriveN/A
2017BMW328dN/A
2017BMW328d xDriveN/A
2017BMW330eN/A
2017BMW330iN/A
2017BMW330i GT xDriveN/A
2017BMW330i xDriveN/A
2017BMW340iN/A
2017BMW340i GT xDriveN/A
2017BMW340i xDriveN/A
2017BMWM140iN/A
2017BMWM2N/A
2017BMWM240iN/A
2017BMWM240i xDriveN/A
2016BMW328dN/A
2016BMW328d xDriveN/A
2016BMW328iN/A
2016BMW328i GT xDriveN/A
2016BMW328i xDriveN/A
2016BMW330eN/A
2016BMW330iN/A
2016BMW335i GT xDriveN/A
2016BMW340iN/A
2016BMW340i xDriveN/A
2016BMWM135iN/A
2016BMWM2N/A
2016BMWM235iN/A
2016BMWM235i xDriveN/A
2015BMW328dN/A
2015BMW328d xDriveN/A
2015BMW328iN/A
2015BMW328i GT xDriveN/A
2015BMW328i xDriveN/A
2015BMW335iN/A
2015BMW335i GT xDriveN/A
2015BMW335i xDriveN/A
2015BMW428iN/A
2015BMW428i Gran CoupeN/A
2015BMW428i xDriveN/A
2015BMW428i xDrive Gran CoupeN/A
2015BMW435iN/A
2015BMW435i Gran CoupeN/A
2015BMW435i xDriveN/A
2015BMW435i xDrive Gran CoupeN/A
2015BMWActiveHybrid 3N/A
2015BMWM135iN/A
2015BMWM235iN/A
2015BMWM235i xDriveN/A
2014BMW328dN/A
2014BMW328d xDriveN/A
2014BMW328iN/A
2014BMW328i GT xDriveN/A
2014BMW328i xDriveN/A
2014BMW335iN/A
2014BMW335i GT xDriveN/A
2014BMW335i xDriveN/A
2014BMWActiveHybrid 3N/A
2014BMWM135iN/A
2014BMWM235iN/A
2013BMW125iN/A
2013BMWActiveHybrid 3N/A
2013BMWM135iN/A

* 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:

11-4694130.3412234336851095MC146080MC391505

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

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