HomeBrake > Brake HydraulicsTRW PML172 Brake Master Cylinder
Part #: PML172

TRW PML172 Brake Master Cylinder

27 vehicles fit this part
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OE Direct Replacement — Bolt-on fit, no modifications needed
Fitment: Audi and Volkswagen, A4, A4 Quattro, A6, A6 Quattro, A8, A8 Quattro, Passat, S4, and S8
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TRW PML172 Brake Master Cylinder

The TRW PML172 brake master cylinder is a direct-fit hydraulic replacement for select Audi and Volkswagen models with a 25.4 mm straight bore and dual M12 x 1.0 outlet threads. Built from aluminum with two mounting holes, it includes a dust boot and gasket/seal for service-ready installation on the listed applications.

Key Features

  • Brake master cylinder for brake hydraulic service
  • 25.4 mm primary bore diameter with straight bore type
  • Aluminum master cylinder body
  • Two port design with primary and secondary outlet thread size M12 x 1.0
  • Dust boot included
  • Gasket or seal included
  • Two mounting holes with 22 mm mounting hole diameter
  • No reservoir, cap, push rod, brake booster, or mounting hardware included

Fitment Details

  • Fits 2001-2003 Audi A8 Quattro, N/A, without electronic stability control.
  • Fits 2001-2003 Audi S8, N/A, without electronic stability control.
  • Fits 2002 Audi S4, N/A, without electronic stability control.
  • Fits 2000-2001 Audi A4, N/A.
  • Fits 2000-2001 Audi A4 Quattro, N/A.
  • Fits 2000-2001 Audi A6, N/A.
  • Fits 2000-2001 Audi A6 Quattro, N/A.
  • Fits 2000-2001 Audi S4, N/A.
  • Fits 2001 Volkswagen Passat, N/A, without electronic stability control.
  • Fits 2000 Volkswagen Passat, N/A.
  • Fits 1999 Audi A4 Quattro, N/A, from chassis/VIN 8D-X-200 001.
  • Fits 1997-1999 Audi A8, N/A.
  • Fits 1997-1999 Audi A8 Quattro, N/A.
  • Fits 1999 Volkswagen Passat, N/A, from chassis/VIN 3B-X-491 581.

What This Part Helps Address

  • Low or inconsistent brake pedal response
  • Internal hydraulic leakage in the master cylinder
  • Brake fluid loss at the cylinder body or outlet ports
  • Pedal travel issues caused by worn hydraulic seals
  • Brake system performance concerns on Audi A4, A6, A8, S4, S8, and Volkswagen Passat applications

Installation Notes

Verify the vehicle’s brake system configuration before installation, especially electronic stability control coverage and VIN breakpoints listed in the fitment data. Confirm the 25.4 mm bore, M12 x 1.0 outlet threads, and two-hole mounting pattern match the original unit on your Audi or Volkswagen. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Quality Assurance

TRW brake hydraulics are built for OE-style service replacement, with aluminum construction and included sealing components to support proper hydraulic function on the specified vehicles. The TRW PML172 is identified for use on 1997-2003 Audi and 2000-2001 Volkswagen Passat applications listed above.

BrandTRW
Part NumberPML172
Reservoir MaterialNone
Dust Boot IncludedYes
Mounting Hardware IncludedNo
Gasket Or Seal IncludedYes
Mounting Hole Quantity2
Master Cylinder Bore Diameter25.4
Bleeder Screw IncludedNo
Piston Quantity2
Brake Booster IncludedNo
Master Cylinder Cap IncludedNo
Master Cylinder MaterialAluminum
Push Rod IncludedNo
Reservoir IncludedNo
Bleeder Hoses IncludedNo
Sensor IncludedNo
Mounting Hole Diameter22
Port Quantity2
Mounting Bracket IncludedNo
Bore TypeStraight
Secondary Outlet Thread SizeM12 - 1.0
Primary Outlet Thread SizeM12 - 1.0
Brake Pressure Switch RequiredNo
Brake Pressure Switch(s) IncludedNo
Primary Bore Diameter25.4

This part fits 27 vehicles. Search below:

YearMakeModelSubmodelLitersCylindersFuel TypePositionNotes
2003AudiA8 QuattroL4.2LV8N/AWithout electronic stability control
2003AudiS8BaseN/AWithout electronic stability control
2002AudiA8 QuattroBase4.2LV8N/AWithout electronic stability control
2002AudiS4AvantN/AWithout electronic stability control
2002AudiS8BaseN/AWithout electronic stability control
2001AudiA4Base1.8LL4N/A
2001AudiA4 QuattroAvant1.8LL4N/A
2001AudiA6BaseN/A
2001AudiA6 QuattroBase2.8LV6N/A
2001AudiA8 QuattroL4.2LV8N/AWithout electronic stability control
2001AudiS4Base2.7LV6N/A
2001AudiS8BaseN/AWithout electronic stability control
2001VolkswagenPassatGLX 4 MotionN/AWithout electronic stability control
2000AudiA4Base2.8LV6N/A
2000AudiA4 QuattroBase1.8LL4N/A
2000AudiA6BaseN/A
2000AudiA6 QuattroBase2.8LV6N/A
2000AudiS4Base2.7LV6N/A
2000VolkswagenPassatGLS1.8LL4N/A
1999AudiA4 QuattroBaseGASN/AFrom Chassis/VIN 8D-X-200 001
1999AudiA8BaseN/A
1999AudiA8 QuattroBaseN/A
1999VolkswagenPassatGLS2.8LV6N/AFrom Chassis/VIN 3B-X-491 581
1998AudiA8BaseN/A
1998AudiA8 QuattroBaseN/A
1997AudiA8BaseN/A
1997AudiA8 QuattroBaseN/A

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