Dorman 47423 Power Brake Booster Check Valve

Brand Dorman 47423
Color/Finish Black
Fitting Outlet Angle Straight
Grommet End Outside Diameter 0.334
Hose End Outside Diameter 0.331
Material Plastic
Outlet Quantity 1
Package Contents 1 Check Valve
Valve Opening Size (in) 0.2 in
Fits Audi and Volkswagen · 22 vehicles

OE-style fit. Matches the original valve's fit and function for straightforward replacement.

Durable plastic. Built for reliable performance in brake booster vacuum systems.

Black finish. Clean, discreet appearance for a factory-like look.

Cross-references 058905291D for the same application. See all 1.

$33.17Free shipping
In stock · usually ships same day before 1pm CST
Step 1 — Confirm fitment
Free return shipping if it doesn't fit when you check fitment here first.
Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $33.17
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.

Power Brake Booster Check Valve for Audi and Volkswagen

This Dorman power brake booster check valve is built to match the fit and function of the original valve on specified vehicles. It is engineered for durable, reliable performance in brake booster vacuum control, with a black plastic body and straight outlet design.

Key Features

  • Direct-fit power brake booster check valve for specified Audi and Volkswagen applications
  • Plastic construction with black finish
  • Straight fitting outlet angle for OE-style routing
  • One outlet configuration
  • Valve opening size: 0.2 in
  • Grommet end outside diameter: 0.334 in
  • Hose end outside diameter: 0.331 in

Detailed Description

Dorman Part Number 47423 is a replacement power brake booster check valve designed for vehicles that use a 3-port brake booster vacuum setup. It is compatible with 1999-2005 Audi A4, 1999-2005 Audi A4 Quattro, and 1998-2005 Volkswagen Passat applications listed in the fitment data. This part helps maintain proper one-way vacuum flow to the brake booster, supporting consistent brake pedal feel and system operation. This part cross-references OE part number 058905291D for the same application.

What It Helps Address

  • Brake pedal that feels hard or requires extra effort
  • Loss of vacuum retention in the brake booster circuit
  • Vacuum leakage at the booster check valve connection
  • Incorrect airflow direction through the booster vacuum line
  • Replacement needs for a worn or cracked OE-style valve

Installation Notes and Tips

Verify the vehicle uses a 3-port configuration before ordering. Match the hose and grommet dimensions to the existing vacuum line and booster connection for proper fitment. Inspect the surrounding vacuum hose and grommet condition during replacement to help ensure a secure seal and correct valve operation.

Quality Assurance

Dorman designs this check valve to match original fit and function on specified vehicles and to deliver dependable service in brake system applications. The part is engineered for durability and reliable performance.

This part fits 22 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelPositionNotes
2005AudiA4N/Aw/3 Ports
2005AudiA4 QuattroN/Aw/3 Ports
2005VolkswagenPassatN/Aw/3 Ports
2004AudiA4N/Aw/3 Ports
2004AudiA4 QuattroN/Aw/3 Ports
2004VolkswagenPassatN/Aw/3 Ports
2003AudiA4N/Aw/3 Ports
2003AudiA4 QuattroN/Aw/3 Ports
2003VolkswagenPassatN/Aw/3 Ports
2002AudiA4N/Aw/3 Ports
2002AudiA4 QuattroN/Aw/3 Ports
2002VolkswagenPassatN/Aw/3 Ports
2001AudiA4N/Aw/3 Ports
2001AudiA4 QuattroN/Aw/3 Ports
2001VolkswagenPassatN/Aw/3 Ports
2000AudiA4N/Aw/3 Ports
2000AudiA4 QuattroN/Aw/3 Ports
2000VolkswagenPassatN/Aw/3 Ports
1999AudiA4N/Aw/3 Ports
1999AudiA4 QuattroN/Aw/3 Ports
1999VolkswagenPassatN/Aw/3 Ports
1998VolkswagenPassatN/Aw/3 Ports
Directly replaces or cross-references 1 part number
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
058905291D