Spicer 070SC128 Front Steering Knuckle Lower Kingpin Cap Plate (Replaces 37299)

Maintain perfect steering geometry, protect your internal steering knuckle bearings, and prevent hazardous wheel slop with this genuine Spicer Front Steering Knuckle Lower Kingpin Cap Plate. Custom-engineered by Dana as a direct tier-one original equipment manufacturer (OEM) replacement component, this high-durability plate (Part Number: 070SC128) is built to withstand extreme wheel loads, heavy cargo weight distributions, and punishing road environments. It directly replaces superceded legacy part number 37299.

On commercial vehicles, heavy-duty vocational fleets, and line-haul transport trucks, the steering knuckle relies on a high-strength kingpin assembly rather than a standard light-duty ball joint to pivot smoothly under massive freight loads. The lower kingpin cap plate acts as a structural seal at the absolute bottom of the steering assembly. It serves two vital mechanical roles: it structurally retains the lower kingpin bushing and thrust bearings securely inside the knuckle bore, and it acts as an airtight, grease-retaining seal. Over high operating hours, road debris exposure, or severe winter road salt contamination, the factory cap plate can rust out, warp, or crack under immense vibration. A compromised lower cap plate allows high-pressure grease to escape, leading to immediate water contamination and dirt invasion. This starves the internal needle bearings of lubrication, manifesting as a dangerous "death wobble," stiff or binding steering wheels, uneven front tire wear, and failed commercial vehicle safety inspections. Replacing the worn plate with this authentic forged-steel Spicer component ensures your front-end architecture is completely sealed to factory standards.

Precision-machined from ultra-high-tensile structural steel alloy by Dana Spicer—the global benchmark in commercial vehicle drivetrain and steering engineering—this lower kingpin plate features a thick, warp-resistant mounting flange and precise bolt-hole alignments to guarantee a flush, leak-free seal against the steering knuckle face. Engineered to handle extreme rotational friction and continuous vertical load spikes, it provides a solid foundation for your front steer axle rebuild. Sourcing this genuine OEM component guarantees that your vehicle's steering track alignment limits match original fleet engineering blueprints exactly.

Component Highlights:

• Direct OEM Supercession Upgrade: Specifically updates and replaces older legacy part number 37299, incorporating modern metallurgy and optimized corrosion resistance.

• Leak-Proof Grease Retention: Engineered with a precision-ground mating surface to lock high-viscosity grease within the lower kingpin pocket, safeguarding internal bearings from moisture.

• Forged Structural Durability: Fabricated from premium micro-alloy steel to prevent plate deformation, keeping the lower kingpin components tightly retained during hard curb impacts or heavy braking.

• Commercial Vehicle Grade Precision: Built to the identical tolerances, dimensions, and balance metrics used by heavy-duty commercial truck assembly lines worldwide.

Axle & Fitment Specifications:

• Axle Component Location: Front Steer Axle — Steering Knuckle Assembly (Lower Position).

• Superceded Part Numbers: Replaces Dana Spicer 37299, 070-SC-128.

• Material Composition: Forged Heavy-Gauge Steel Alloy.

• Fastener Style: Multi-bolt mounting layout (Hardware and gasket/shims sold separately; always replace shims and seal rings during installation to ensure proper kingpin preload).

• Common System Applications: Fits various heavy-duty Class 6, 7, and 8 commercial vehicle front steer axles from major manufacturers including Freightliner, International, Peterbilt, Kenworth, Volvo, Mack, and commercial bus platforms equipped with Dana Spicer steering assemblies.