63900-120 – Piper Aircraft Nose Gear Steering Linkage Bushing
Available now on the Airparts.aero Marketplace.
The Piper Aircraft 63900-120 is a genuine OEM, flight-critical sleeve bushing, specifically designed for use in the nose landing gear steering linkage system on various Piper aircraft. This precision-machined component serves as an essential pivot point and replaceable wear surface within the complex geometry of the steering mechanism. Its primary function is to allow smooth, low-friction articulation of the steering rods and bellcranks while protecting the more expensive structural components from wear and elongation, ensuring accurate and responsive nosewheel steering.
Fabricated from a high-quality bearing material, likely a bearing bronze alloy specified by Piper for its excellent load-carrying capacity and wear resistance, this bushing is engineered for durability in a demanding environment. It is designed to be installed with a precise fit into its housing, providing a dimensionally stable bore for the connecting bolts or pins. Maintaining the tight tolerances within the steering linkage is crucial for preventing shimmy and ensuring positive directional control during ground operations.
Key Features
Genuine Piper Aircraft OEM Part: Guarantees the precise dimensions, correct bearing alloy material, and quality standards specified for the nose gear steering system.
Provides Low-Friction Pivot Point: Ensures smooth articulation of the steering linkage components for responsive ground handling.
Replaceable Wear Surface: Acts as a sacrificial element, protecting the structural integrity of the steering arms, bellcranks, and mounting structure from wear.
High Load Capacity Bearing Material: Typically manufactured from a high-quality bearing bronze alloy (e.g., SAE 660) selected for its durability and anti-galling properties against steel pins or bolts. (Material must be confirmed by OEM documentation).
Maintains Steering Linkage Integrity: Prevents excessive free play ("slop") from developing due to wear, which is critical for preventing nosewheel shimmy and maintaining directional control.
Technical Specifications
Part Number: 63900-120
Component Type: Sleeve Bushing / Plain Bearing
OEM Manufacturer: Piper Aircraft, Inc.
Application Location: Nose Landing Gear Steering Linkage Pivot Points.
Material: Likely Bearing Bronze (e.g., SAE 660 / CDA 932). Material must be confirmed by OEM documentation or material certification.
Finish: Natural (as machined).
Dimensions: Specific Inside Diameter (ID), Outside Diameter (OD), and Length (L) must be confirmed via Piper documentation or part inspection.
Installation: Typically Press Fit (Requires specific interference fit with housing bore).
Aircraft Compatibility
The 63900-120 is specified for use in the nose gear steering linkage on various Piper aircraft models, particularly retractable gear singles and twins. Common applicable families include, but are not limited to:
PA-28R Series: Arrow
PA-32R Series: Lance, Saratoga SP RG
PA-34 Series: Seneca
PA-44 Series: Seminole
PA-46 Series: Malibu, Mirage, Meridian, M-Class
Crucial Note: Verification against the specific aircraft's current Illustrated Parts Catalog (IPC) is mandatory to ensure correct part number applicability.
Applications
Primary pivot bushing for nose gear steering rods, bellcranks, and links.
Replacement part for bushings found to be worn (exceeding wear limits specified in the maintenance manual), corroded, or damaged, often identified during shimmy damper servicing or gear inspections.
Why Choose 63900-120?
Choosing the genuine Piper 63900-120 bushing is essential for maintaining safe and precise ground handling. Worn bushings in the nose gear steering linkage are a primary cause of nosewheel shimmy, which can range from a minor annoyance to a dangerous loss of control during takeoff or landing rollout. The OEM part guarantees the correct high-strength bearing material and the precise dimensional tolerances required for a proper fit. Using a non-certified bushing risks premature wear, excessive free play leading to shimmy, or improper fit causing binding in the steering system.
The 63900-120 operates under principles of tribology as a plain bearing, designed to function primarily in the boundary lubrication regime within the steering linkage. The specified bearing material, likely a leaded tin bronze such as SAE 660 (CDA 932), is engineered for this role. The copper matrix provides strength, while tin adds hardness. The crucial lead particles dispersed within act as a solid lubricant, smearing across the surface under load to prevent galling (adhesive wear) between the bushing and the steel pivot pin, especially during the low-speed, high-load conditions experienced during ground maneuvering. The inherent porosity of the bronze also retains grease applied during maintenance, providing a lubricant reservoir. The interference fit during installation is vital; it secures the bushing, preventing rotation within its housing and minimizing fretting corrosion, ensuring the long-term integrity of the steering linkage geometry.
Note: This is a flight-critical landing gear component. Bushings are wear items and are typically replaced when wear exceeds limits specified in the maintenance manual. Installation requires specialized tooling (e.g., an arbor press with appropriately sized installation mandrels) to ensure the bushing is pressed in straight and without damage. The housing bore must be precisely measured. After installation, the inner diameter of the bushing MUST be reamed or honed to achieve the final, precise running clearance for the mating pivot pin as specified by Piper. Consult the applicable maintenance manual for lubrication requirements.
Documentation
No public-facing OEM or regulatory documentation was located for this specific part number. All technical data, installation procedures, wear limits, and applicability must be sourced from the official Piper Aircraft Illustrated Parts Catalog (IPC) and Maintenance Manual for the specific aircraft model.