3580-99 – Center Support Bearing – 1350 Series – 1.378″ ID – Notes 3580-34 bearing with dust cap

3580-99 Configuration
Assembly: 3580-34 bearing + dust cap  |  Series: 1350  |  Bore ID: 1.378" (35 mm)  |  Type: Rubber-isolated center support bearing with dust shield

The 3580-99 differs from the base 3580-34 in one important respect: it includes a pressed-steel dust cap that seats over the exposed bearing face on the inboard side of the assembly. This cap is critical in off-road and high-road-spray applications where water and grit enter the bearing from the driveshaft side and erode the ball bearing lubricant.

Without the dust cap (as on the 3580-34 alone), the inboard bearing face is exposed to the rotating stub shaft -- any water ingress from underbody spray travels directly into the bearing. The cap creates a labyrinth seal path that significantly reduces contamination ingress. For vehicles operating in wet climates, routinely towing, or driven off-road, the 3580-99 with integrated dust cap is the correct specification. The 1350-series application uses 1.188" U-joint cap diameter; bore ID here is 1.378" (35 mm).