Lippert 2023134018 Unitized Oil Seal -- 2.25" ID, 5,200-8,000 lb Axles, 2-Pack
A two-pack of factory-spec unitized oil seals designed to keep bearing grease contained and road contamination out on Lippert and compatible trailer axles rated from 5,200 to 8,000 lbs. One pack covers both hubs on a single axle.
Wheel bearing failure is one of the most preventable -- and most catastrophic -- roadside emergencies an RV or trailer owner can face. The oil seal is the last line of defense between your bearing assembly and road grime, water, and brake dust. When the seal fails, lubricant escapes and contamination enters, accelerating bearing wear and risking a wheel-off event.
Lippert part number 2023134018 (also cross-referenced as PP-OSK-1 and vendor part 08-7926) is a unitized oil seal -- meaning the inner seal lip, spring, and outer casing are assembled as a single press-fit unit for consistent, repeatable installation without hand-packing or shimming individual components.
Each two-pack contains enough seals for both hubs on one axle, making this the correct quantity to buy when doing a full axle service on a single trailer axle.
Seal lip, garter spring, and outer case assembled as one unit -- no separate components to align during installation.
Precision fit for 2.25-inch spindle shaft diameter, common on 5,200 to 8,000 lb rated trailer axles.
Outer diameter sized to press into the 3.371-inch hub bore for a secure, leak-free fit without adhesive.
Both seals in one purchase -- enough to service the inner seal position on both hubs of a single axle.
Unlike a standard lip seal that is pressed in separately from its spring and retainer, a unitized seal arrives pre-assembled with all components bonded or clipped together. This design eliminates the most common installation errors -- cocked seals, misaligned lips, and spring pop-out -- and provides a consistent sealing pressure from the first mile.
This oil seal is located at the inboard (inner) face of the hub, between the inner wheel bearing and the spindle shoulder. Its job is to prevent the bearing lubricant -- whether grease or oil-bath -- from migrating inward onto the brake shoes or rotor while also blocking road spray and dust from contaminating the bearing assembly.
Typical service intervals for this component:
The 2.25-inch spindle shaft diameter is the standard dimension on Lippert (formerly Dexter) axles in the 5,200 to 8,000 lb capacity range. If your axle spindle measures 2.25 inches across the shaft where the seal rides, and your hub bore accepts a 3.371-inch outer diameter seal, this is the correct part. Always measure before ordering if your axle documentation is unavailable.
This seal is used on Lippert-manufactured axles (formerly sold under the Dexter Axle brand after Lippert's acquisition) as well as many private-label and OEM axles built to the same spindle standard. Common applications include:
Axle weight rating alone does not uniquely identify seal size. Some 7,000 lb and 8,000 lb axles use different spindle diameters depending on configuration and model year. Measure your spindle shaft at the seal journal and confirm the hub bore accepts a 3.371" OD seal before pressing this part in. Using an undersized seal will result in immediate leakage.
Unitized oil seals should be pressed in squarely using a seal driver or a properly sized socket that contacts only the outer case of the seal -- never the lip. Drive the seal flush with or slightly below the hub face depending on your hub design. Lubricate the outer case lightly with clean bearing grease before pressing to ease installation and prevent galling the bore.