Bearings & Seals

What Are Engine Bearings & Seals?

Bearings and seals are among the most fundamental components in any engine's drivetrain system. Bearings reduce friction between moving parts — allowing shafts, gears, and rotating assemblies to spin freely and efficiently under load. Seals work in tandem, keeping lubricating oil in and contaminants like dirt, dust, and moisture out. Together, they protect the precision surfaces inside your engine and drivetrain from premature wear, heat buildup, and catastrophic failure.

From crankshaft and camshaft bearings deep inside the engine block to output shaft seals at the transmission and differential, virtually every rotating assembly in a vehicle depends on quality bearings and seals to function correctly. Neglecting these components — or installing substandard replacements — can lead to oil leaks, excessive heat, noise, vibration, and eventually serious mechanical damage.

Types of Bearings & Seals

Not all bearings are created equal, and choosing the correct type for your application matters. Common types you'll encounter in drivetrain service include:

• Tapered Roller Bearings – Engineered to handle both radial and axial (thrust) loads simultaneously, making them a staple in wheel hubs, differentials, and transmissions.
• Ball Bearings – Ideal for applications with lighter radial loads and high rotational speeds, often found in alternators, idler pulleys, and support bearings.
• Cylindrical Roller Bearings – Built for high radial load capacity, frequently used in gearboxes and heavy-duty drivetrains.
• Needle/Journal Bearings – Thin-profile bearings that fit in tight spaces, common in engine connecting rods and universal joints.
• Oil Seals & Lip Seals – Flexible sealing elements that prevent lubricant leakage around rotating shafts, critical at crankshaft snouts, rear main seals, and axle ends.

What to Look for When Shopping Bearings & Seals

When selecting bearings or seals, prioritize OE-equivalent or better tolerances. Precision-ground raceways, quality cage materials, and correct seal lip geometry all contribute to longevity. Always verify the part number fits your specific application — even small dimensional differences can cause premature failure. For seals, pay attention to the material: nitrile rubber suits most general applications, while high-temperature environments may call for fluoroelastomer or silicone compounds.

Top Brands in Bearings & Seals

SKF is one of the most recognized names in bearing and seal technology worldwide. Founded in 1907, SKF has served as a trusted OE supplier to the automotive industry, producing seals, wheel bearings, ball bearings, roller bearings, and hub assemblies for a wide range of vehicles. Their product lineup spans everything from passenger car drivetrain kits to high-performance components used in motorsport applications.

Bower has been a cornerstone of American bearing manufacturing since 1904, when the brand's founding thrust-controlling roller bearing design first proved its mettle. Today, operating as part of NTN-Bower Corporation, Bower's tapered roller bearings are shipped from U.S. plants in Macomb, IL and Hamilton, AL, and are specified by OEMs and fleet managers across North America — particularly in heavy-duty truck, agriculture, and construction applications.