WHEEL SEALS

Wheel Seals For Peterbilt Trucks

Wheel seals keep axle lubricant in the hub and road contamination out — on oil-lubricated drive and trailer axles, a failed wheel seal allows gear oil to leak onto the brake linings, creating an immediate out-of-service condition and a dangerous braking deficiency. On grease-lubricated steer axles, failed seals allow bearing grease to escape and contamination to enter the bearing cavity. We carry inner and outer wheel seals for Peterbilt drive, steer, and trailer axle applications from trusted brands including National, SKF, and Stemco.

Frequently asked questions about wheel seals

How do I identify a leaking wheel seal on a Peterbilt during a pre-trip inspection?

During a walk-around inspection, look for oil streaking on the inside face of the wheel, oil residue on the brake drum or backing plate, or a wet ring on the axle housing just inboard of the hub. Even a minor seep on the brake side — any oil contact with the brake lining — is an immediate out-of-service condition under FMCSA regulations. A steer axle seal leak typically presents as grease on the inside of the wheel and surrounding hub area rather than oil, since steer axles use packed grease rather than oil lubrication.

What causes wheel seals to fail prematurely on a Peterbilt?

Improper installation is the leading cause of premature wheel seal failure — a seal that's cocked during installation, installed without proper tooling, or seated against a worn or pitted spindle surface will fail early. Running the hub oil at an incorrect level (too high causes pressure buildup against the seal; too low starves bearings) also affects seal life. Contaminated or degraded lubricant with metallic particles from bearing wear can damage the seal lip as well. On high-mileage trucks, a worn spindle surface where the seal rides is a common source of repeat seal failures.

Should I replace wheel bearings at the same time as wheel seals on a Peterbilt?

Not automatically, but always inspect the bearings when the seal is out. Since the hub must come off to access the seal, the marginal additional time to clean, inspect, and measure the bearings is well worth it. Bearings showing pitting, brinelling, or heat discoloration should be replaced. If the bearings are in good condition, they can be reused with fresh lubricant and a new seal. On a high-mileage hub that's had a seal failure with possible lubricant contamination, replacing both seal and bearings together is the prudent choice.

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