Restore the integrity of legacy motor assemblies with the A.O. Smith (AOS) Century Motor Thru Bolts, engineered for durability and precise alignment in residential, commercial, and light industrial equipment. Although produced as a discontinued item by the original manufacturer, these thru bolts remain a trusted option for technicians and DIY maintainers who need to keep A.O. Smith/Regal Beloit, Century/Regal Beloit, Franklin Electric, and General Electric motors running smoothly.

Key specifications and compatibility

• Thread size: 10-32
• Overall length: 8-1/8" (8.125")
• Threaded end length: 2"
• Type: Thru-bolt designed for motor mounting and end-bell assemblies
• Replaces: 5271-45, 620003
• Compatible motor brands: A.O.Smith / Regal Beloit, Century / Regal Beloit, Franklin Electric, General Electric
• Part lineage: Century Electric Motors / A.O. Smith Electric Motors legacy replacement bolt

Why this thru bolt matters for your motor project

When motor components need a secure, true-fit fastener, the 10-32 x 8-1/8" thru bolt with a 2" threaded end delivers consistent tension and alignment across the mounting interface. This is especially critical for maintaining proper shaft alignment, minimizing vibration, and extending bearing life in pumps, fans, blowers, and other driven equipment that rely on robust bolt-through assemblies.

Who should consider this part

Ideal for maintenance professionals, equipment technicians, and seasoned hobbyists performing motor replacements or servicing legacy systems where original parts have been discontinued. If your project involves A.O. Smith or Century motors, or equipment built by Regal Beloit, Franklin Electric, or General Electric that uses thru-bolt fasteners, this part is a practical, compatible choice.

Practical use cases and installation tips

• Use for replacing worn or damaged thru-bolts in motor housings where a secure through-bolt connection is required.
• Verify your motor model and mounting pattern before installation to ensure 10-32 thread compatibility and the correct overall length.
• Inspect mating threads and clean the bolt holes prior to assembly to prevent cross-threading and ensure full engagement of the 2" threaded portion.
• When reassembling, match with corresponding nuts and hardware designed for thru-bolt applications and torque to the motor manufacturer’s specifications where available.

Additional notes

As a discontinued-by-manufacturer item, stock levels can vary. This replacement thru bolt remains a dependable option for preserving legacy motor performance and extending the service life of equipment that relies on A.O. Smith, Century, and related brands. If you’re restoring an older motor, this part offers a concrete, dimensionally consistent solution that aligns with the original design intent and mounting geometry.