The Wacker Neuson 5200020165 is a genuine OEM O-Ring designed for APT4S and APT4T series self-priming pumps. Sourced directly from Wacker Neuson, this O-Ring meets the exact material and dimensional specifications of the original part — ensuring a proper seal across all covered configurations, including cold weather and electric brake variants. Compatibility extends to the APT4S Pump with Skid, APT4S Pump with Skid Cold Weather, APT4T Pump with Surge Brake, APT4T Pump with Electric Brake, APT4T Pump with Surge Brake Cold Weather, and APT4T Pump with Electric Brake Cold Weather. When a seal starts to fail, fluid loss and pressure drop follow fast — replace it with the same part the machine was built with.
Key Features
- Exact OEM Material Grade — Manufactured to Wacker Neuson's original compound and durometer specification, so the ring compresses and seats correctly without over-deforming or leaking under pump operating pressure.
- Drop-In Replacement — Dimensionally identical to the original; seats into the same groove without reworking mating surfaces or hardware.
- Broad APT4 Series Coverage — A single part number covers APT4S and APT4T pump configurations including standard, electric brake, surge brake, and cold weather variants.
- Maintains Pump Output Integrity — A correctly seated O-Ring holds the pressure differential the pump relies on to move fluid efficiently; a degraded seal allows bypass that robs flow rate and prime.
- Fluid System Safety — A failed O-Ring in a pump circuit can cause uncontrolled fluid seepage around fittings and housings; replacing with a confirmed OEM-spec seal keeps the fluid path contained and the work area safe.
An O-Ring is a circular elastomeric seal that sits in a machined groove between two mating surfaces or around a fitting, creating a pressure-tight barrier that prevents fluid from escaping the pump circuit. In self-priming pump applications like the APT4S and APT4T, maintaining that seal is critical — even a minor leak path at the O-Ring allows air to enter or fluid to escape, causing the pump to lose prime or deliver reduced output. When an O-Ring becomes compressed, cracked, or chemically degraded, replacing it promptly with a correctly specified part restores the sealed system the pump depends on to operate at full capacity.
Part Details
| Part Number | 5200020165 |
|---|---|
| Brand | Wacker Neuson |
| Part Type | Genuine OEM |
| Description | O-Ring |
Compatibility & Fitment
| Name | Model | Machine Number |
|---|---|---|
| APT4S Pump w/Skid, Cold Weather | APT4S CW | 5200019798 |
| APT4T Pump, Electric Brake, Cold Weather | APT4T CW | 5200019793, 5200019792 |
| APT4T Pump, Surge Brake | APT4T | 5200019643, 5200019644 |
| APT4S Pump w/Skid | APT4S | 5200018977 |
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.
