OVERVIEW
Genuine VW/Audi inner tie rod, part number 420-422-821-A. This steering linkage component connects the steering rack to the separate outer tie rod on the specified Audi R8 applications. The inner joint allows the linkage to articulate as rack movement is transmitted toward the front wheel.
Technical details
- Original part number: 420-422-821-A / 420422821A.
- Inner steering tie rod / axial joint for the specified Type 42 R8 steering gear.
- Includes the inner joint housing, rod and threaded outer connection shown in the source photo.
- Confirmed dealer-catalog assignments include left and right inner steering positions as specified in the fitment table.
- The outer tie rod end, protective bellows, clamps and complete steering rack are separate components.
- Supplied as one inner tie rod.
Common reasons to replace
Excessive play at the inner joint, binding articulation, damaged connection threads or a bent rod can require replacement. Steering looseness, a knock when steering direction changes or unstable alignment can prompt a linkage inspection. A torn bellows can also expose the joint and rack area to contamination.
These symptoms can have other causes, including the outer tie rod, steering rack, wheel bearings or suspension joints. Check the inner joint directly and inspect the rest of the linkage before replacing parts. Replacing this rod alone will not correct a worn rack or damaged outer joint.
Installation and service notes
Confirm the vehicle's steering gear part number, VIN assignment and mounting position before ordering. Use the factory procedure and appropriate tools to support the rack and remove the inner joint without transmitting unnecessary force through the steering gear. Inspect the bellows and clamps and replace damaged protective parts.
Follow the vehicle-specific requirements for tightening, locking provisions and replacement hardware. The threaded connection forms part of the steering toe adjustment; record the original setting only as an initial assembly reference. Arrange a proper wheel alignment after replacement, then check steering movement, bellows positioning and all attachment points.
Fitment
| Vehicle | Model year | Engine | Required configuration |
|---|---|---|---|
| Audi R8 Coupe | 2008 | 4.2L V8 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
| Audi R8 Coupe | 2010 | 4.2L V8 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
| Audi R8 Coupe | 2010 | 5.2L V10 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
| Audi R8 Coupe | 2012 | 5.2L V10 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
| Audi R8 Spyder | 2014 | 4.2L V8 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
| Audi R8 V10 Plus Coupe | 2014 | 5.2L V10 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
| Audi R8 GT Coupe | 2012 | 5.2L V10 gasoline | Type 42 quattro; right inner steering position; confirm steering gear assignment |
| Audi R8 Spyder | 2012 | 4.2L V8 gasoline | Type 42 quattro; right inner steering position; confirm steering gear assignment |
| Audi R8 Spyder | 2015 | 4.2L V8 gasoline | Type 42 quattro; left inner steering position; confirm steering gear assignment |
Confirm compatibility by VIN and installed steering gear. The table identifies verified applications; do not infer compatibility with a different steering position or later-generation R8.