Flare Nut Spanners

About Flare Nut Spanners

Flare nut spanners, also known as brake pipe spanners or line wrenches, are specialised tools designed for working with hexagonal nuts on brake lines, fuel lines, and hydraulic fittings. Unlike standard open-ended spanners, these feature a near-closed ring design with a small slot that grips five of the six sides of a nut whilst accommodating the pipe or tube passing through. This crucial design prevents rounding-off of soft metal fittings—a common problem when using conventional spanners on delicate hydraulic unions.

MyToolShed.co.uk stocks a comprehensive range of flare nut spanners from trusted brands including Sealey, Draper, Facom, and Elora. Available in both metric and imperial sizes, our selection includes individual spanners, complete sets, and advanced designs such as flexible head and ratcheting models. Whether you're a professional motor technician or DIY enthusiast, these precision-engineered tools provide the grip and leverage needed for brake system work, air conditioning lines, and hydraulic equipment maintenance without damaging critical fittings.

Applications

• Motor Vehicle Technicians: Brake system repairs, hydraulic line maintenance, and fuel system work on cars, vans, and commercial vehicles
• MOT Testers: Brake pipe inspection and replacement during annual testing procedures
• HGV and Plant Mechanics: Maintaining hydraulic systems on lorries, buses, agricultural machinery, and construction equipment
• Mobile Mechanics: On-site brake and hydraulic repairs requiring compact toolkits
• Motorcycle Technicians: Working on motorbike brake lines in confined spaces
• Heating Engineers: Compression fittings and hydraulic connections in heating systems
• Air Conditioning Engineers: Refrigerant line connections without damaging soft copper and aluminium fittings
• DIY Enthusiasts: Home mechanics performing brake maintenance and vehicle restoration work

Choosing The Right Flare Nut Spanners

Metric or Imperial: Modern European and Japanese vehicles use metric sizes (typically 8mm to 22mm), whilst older British vehicles and some American equipment require imperial sizes (3/16" to 3/4" AF). Professional workshops benefit from stocking both systems.

Individual Tools or Sets: For occasional use, individual spanners offer economy. However, complete sets (3-piece, 5-piece, or 6-piece configurations) provide better value for professional technicians and regular users, ensuring you have the right size for any job.

Standard vs Flexible Head: Fixed-head spanners suit most applications with maximum strength. Flexible head models significantly improve access in confined engine bays and around suspension components—an excellent investment for professional automotive work at MyToolShed.co.uk.

Build Quality: Professional-grade chrome vanadium construction from established brands ensures accurate sizing, durability, and corrosion resistance. Quality tools prevent rounded fittings and provide reliable long-term service.

Safety Information

Correct Tool Selection: Always use the correctly sized flare nut spanner. Ill-fitting tools can round off nut corners, creating dangerous situations on brake systems where leaks can result in complete brake failure.

Brake Fluid Handling: Wear protective gloves and eye protection when working with brake systems. Brake fluid is corrosive and attacks paintwork—wash off spills immediately with water.

System Pressure: Never loosen hydraulic fittings whilst systems are under pressure. Air conditioning refrigerant must be recovered by qualified technicians before disturbing connections. Depressurise fuel systems before working on fuel lines.

Frequently Asked Questions

What's the difference between a flare nut spanner and a standard open-ended spanner?

A flare nut spanner grips five of the six sides of a nut with its near-closed ring design, whilst accommodating the brake or fuel line through a small slot. Standard open-ended spanners only contact two sides, making them far more likely to round off soft metal nuts on hydraulic fittings.

Do I need both metric and imperial flare nut spanners?

This depends on the vehicles you work with. Modern European and Japanese vehicles exclusively use metric fittings. However, if you maintain classic British cars, American vehicles, or older equipment, you'll need imperial sizes. MyToolShed.co.uk stocks both to suit all requirements.

Are flexible head flare nut spanners worth the extra cost?

For professional technicians and serious DIY enthusiasts, yes. The ability to angle the head significantly improves access in tight engine bays and around suspension components, often making the difference between completing brake system jobs easily or struggling for hours with restricted access.