Steering gear Audi R8 Coupe year 2014 5.2i V10 423.422.065.G

Part Number: 423.422.065.G (423422065G)

Application: Audi R8 Coupe & Spyder (Facelift)

Engine: 5.2L V10 / 4.2L V8

Model Year: 2013–2015

The 423.422.065.G is the definitive steering rack for the final evolution of the first-generation Audi R8. Unlike the modern “EPS” (Electric Power Steering) systems found in the newer R8 4S, this unit is a Hydraulic Power Steering rack. It is prized by enthusiasts for providing a level of mechanical feedback and “road feel” that is often lost in fully electric systems.

Technical Specifications

• System Type: Hydraulic Rack-and-Pinion.

• Ratio: Speed-sensitive “Servotronic” (variable assistance based on vehicle speed).

• Cooling: Integrated cooling loop connections to manage hydraulic fluid temperature during track use.

• Mounting: 3-point reinforced chassis mounting points.

Key Engineering Features

• Servotronic Valve: The “G” revision features a specific solenoid valve (Servotronic) that increases steering weight at high speeds for stability and lightens it during low-speed maneuvers (parking).

• Feedback Calibration: Specifically valved for the mid-engine weight distribution of the R8, ensuring the front end feels “darty” and precise without being twitchy.

• Revision History: The “G” suffix represents the most refined version of this rack, addressing seals and internal friction issues found in the earlier “A” and “C” variants.

Professional Installation & Maintenance

1. Fluid Specification: Requires Audi Genuine Power Steering Fluid (G 004 000 M2).

   • Warning: Never use standard ATF. Using the wrong fluid will swell the internal seals and cause the rack to fail within weeks.

2. System Bleeding: After installation, the system must be bled by turning the steering wheel lock-to-lock several times with the front wheels off the ground while the engine is running. Failure to bleed correctly can cause “groaning” noises and cavitation in the pump.

3. Tie Rods & Alignment: Even if the rack is “Complete,” it is best practice to install new Inner Tie Rods and Outer Tie Rod Ends (420 423 811). A professional 4-wheel alignment is mandatory to reset the “Steering Angle Sensor” (J527) zero-point.

4. Leak Inspection: When sourcing a used or new-old-stock unit, check the rubber gaiters (boots). If there is any fluid inside the boots, the internal seals have failed.

Component Comparison

Inventory Note: This rack is a high-value item for R8 owners looking to restore factory-spec handling. Ensure the Servotr