The Wacker Neuson 5200021739 Square Key is a genuine OEM component designed for APT8T and APT8S series submersible pumps, including Electric Brake, Surge Brake, and Cold Weather variants. As a direct OEM part, the 5200021739 is manufactured to the exact tolerances required for proper shaft-to-component engagement across the full APT8 pump family. Confirmed fitment spans the APT8T Pump with Electric Brake, APT8T Pump with Surge Brake, APT8S Pump with Skid, and all corresponding Cold Weather configurations. When you need an exact replacement, sourcing the genuine Wacker Neuson 5200021739 ensures the fit is correct the first time.
Key Features
- Exact OEM Tolerancing — Manufactured to the precise dimensional spec required for secure shaft keyway engagement in APT8 series submersible pumps.
- Drop-In Shaft Replacement — Seats directly into the existing keyway without modification, restoring positive drive connection between shaft and driven component.
- Broad APT8 Family Coverage — Compatible with APT8T Electric Brake, APT8T Surge Brake, APT8S with Skid, and all Cold Weather variants within the APT8 pump lineup.
- Protects Torque Transfer Integrity — A worn or missing square key allows the shaft and hub to slip, causing loss of pump output and accelerated wear on mating surfaces.
- Genuine Wacker Neuson OEM Part — Sourced directly through the Wacker Neuson parts network, ensuring authenticity and traceability for your service records.
A square key is a small but critical drivetrain component that locks a rotating shaft to a hub, impeller, or gear so that torque is transmitted without slippage. It sits in a machined keyway cut into both the shaft and the mating bore, creating a positive mechanical connection between the two. When a square key wears, shears, or goes missing, the driven component can spin freely on the shaft, resulting in a complete loss of pump function and potential damage to the keyway itself if operation continues.
Part Details
| Part Number | 5200021739 |
|---|---|
| Brand | Wacker Neuson |
| Part Type | Genuine OEM |
| Description | Square Key |
Compatibility & Fitment
| Name | Model | Machine Number |
|---|---|---|
| APT8T Pump, Electric Brake, Cold Weather | APT8T CW | 5200019797, 5200019796 |
| APT8T Pump, Electric Brake | APT8T | 5200019649, 5200019648 |
| APT8S Pump w/Skid | APT8S | 5200018987 |
| APT8S Pump w/Skid, Cold Weather | APT8S CW | 5200019800 |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
