American Grease Stick BLU-10B Brass Brake Line Union Bubble Flare - 6mm M12x1.0

The American Grease Stick (AGS) BLU-10B is a brass brake line union designed to join two hydraulic lines — brake, fuel, or transmission — into a single, leak-proof connection. Constructed from solid brass with a metric M12x1.0 thread and sized for 6mm tube diameter, this union is the correct fitting for joining 6mm GM metric brake lines.

A brake line union is commonly required in long line runs, such as from a dual master cylinder to the rear axle, or any time a damaged section of line must be spliced and repaired. Proper fitment is critical: both the flare type (bubble/ISO) and thread specification must match the existing lines to ensure a safe, leak-free connection.

Key Specifications:

• Material: Brass
• Thread Type: Metric
• Thread Diameter: M12 x 1.0 mm
• Tube Diameter: 6mm
• Flare Type: Bubble (ISO)
• Sold as: 1 per bag

Cross-Reference Part Numbers:

• FMSI Universal: 4238
• NAPA Brakes: 641-3294
• Dorman: 490-339

AGS is a trusted manufacturer of specialty automotive brake, fuel, and transmission line fittings, with decades of experience producing quality hydraulic line components for professional and DIY mechanics alike.