GearWrench Nut Extractor 86177 8mm 5/16 Inch Bolt Biter Driver (Bi Directional Cr-Mo Steel Torsion Zone Black Oxide Rounded Fastener Removal)

GearWrench 86177 Bolt Biter™ 8mm (5/16") Impact Nut Extractor & Driver

The GearWrench 86177 Bolt Biter™ 8mm (5/16-inch) impact nut extractor driver removes severely rounded, stripped, frozen, and rusted hex fasteners across automotive engine compartments, industrial assembly lines, and mechanical equipment. Engineered from high-strength Chrome-Molybdenum (Cr-Mo) alloy steel with an integrated high-torque torsion zone, this impact-rated extraction socket absorbs rotary hammer shock to deliver up to 50 times longer service life than standard cutting extractors. Outfitted with patented bi-directional gripping flutes for removing and retightening compromised hardware, dual-dimension compatibility for 8mm metric and 5/16-inch SAE hardware, a tapered self-seating lead-in throat, and a corrosion-resistant black oxide finish with high-visibility laser-etched markings, it equips professional automotive technicians, fleet mechanics, and industrial millwrights with dependable fastener recovery power.

Best Used For:

• Automotive Engine Bay and Manifold Fastener Removal: Extracting corroded, heat-cycled 8mm (5/16") exhaust heat shield bolts, water pump hardware, and valve cover screws without shearing the head.
• Industrial Machinery Maintenance and Teardowns: Gripping heavily painted, frozen, or stripped machine fasteners securely during plant equipment overhauls and rebuilds.
• Temporary Hardware Alignment and Re-Torquing: Engaging damaged bolt heads in reverse to securely tighten fasteners temporarily when exact replacement hardware is not immediately accessible.

Key Performance & Safety Features

• Bi-Directional Gripping Geometry: Patented tapered internal flutes grip damaged fasteners in counterclockwise extraction mode and clockwise installation mode.
• 50X Extended Tool Lifespan: Specialized non-cutting extraction design grips the fastener body without cutting or weakening the metal, vastly outlasting spiral-flute extractors.
• High-Torque Impact Torsion Zone: Engineered shaft flex zone absorbs sudden torque spikes and percussive impacts from high-power cordless impact drivers.
• Dual-Size Metric and SAE Compatibility: Precision-machined profile engages both 8mm metric and 5/16-inch SAE fasteners with equal holding stability.
• Tapered Self-Centering Throat: Allows the socket to slide easily over mushroomed, flared, and corroded fastener heads without requiring hammer strikes to seat.
• Chrome-Molybdenum (Cr-Mo) Metallurgy: Heavy-duty forged alloy core with a protective black oxide finish repels shop chemicals, cutting fluids, and rust.

What's Included

• (1) GearWrench Bolt Biter™ 8mm (5/16") Impact Nut Extractor & Driver (Model 86177)

Technical Specifications

Pro-Tip: Press the extractor squarely onto the damaged 8mm or 5/16" fastener head before pulling the impact driver trigger; the engineered lead-in taper will automatically draw the internal gripping flutes around the rounded flats for instantaneous breakaway torque.