Product Summary

Longze High-Precision Banjo Bolts (DIN 7643 / SAE J514) are specialized hollow fasteners designed to facilitate fluid transfer in space-constrained hydraulic and fuel systems.

Manufactured in Yongnian, China, our banjo bolts feature precision-drilled cross-holes and a central flow gallery, allowing for high-pressure fluid passage through the bolt itself.

Whether for automotive brake lines, turbocharger oil feeds, or industrial hydraulic manifolds, Longze banjo bolts provide the leak-free reliability and compact orientation required for modern fluid power systems.

• ✔ Burr-Free Cross Holes: Our cross-drilled oil ports undergo a specialized deburring process to ensure smooth fluid flow and prevent damage to internal seals or banjo fittings.

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• ✔ High-Pressure Integrity: Produced from cold-drawn steel or stainless alloys, our hollow shanks are engineered with optimized wall thickness to withstand operating pressures exceeding 200 bar without deformation.

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• ✔ Precision Under-Head Surface: The sealing face under the bolt head is machined to a mirror finish (Ra < 0.8), ensuring a perfect metal-to-metal or gasket-supported seal with copper or bonded washers.

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• Standards: DIN 7643 (Metric), SAE J514 (Imperial), ISO 6149.

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• Thread Range: M8 x 1.0 to M30 x 2.0 | 5/16" to 1-1/4".

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• Hole Configuration: Single Port (Standard) or Multi-Port (Custom).

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• Material Grade: Medium Carbon Steel (Class 8.8 equivalent) | Stainless Steel 304 (A2) & 316 (A4).

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• Surface Finish: Zinc Plated (Clear/Yellow), Zinc-Nickel, Cr6-Free, Passivated.

Mechanical Properties & Material Standards

• Matching the steel grade to the structural requirements of the transmission line.

• Material Type	Grade / Standard	Tensile Strength	Yield Strength	Pressure Rating
  Thép Cacbon	Class 8.8 (10L15/12L14)	800 MPa	640 MPa	Up to 250 Bar
  Stainless 304	A2-70	700 MPa	450 MPa	Up to 200 Bar
  Stainless 316	A4-80	800 MPa	600 MPa	Up to 220 Bar

Standard Cross Arm Dimensions

• Common configurations for standard hydraulic and fuel line assemblies.

• Thread Size (D x P)	Length (L)	Hole Dia (d2)	Hex Size (s)	Flow Rate (Est.)
  M10 x 1.0	19 - 24 mm	4.0 mm	14 mm	Low (Brake)
  M12 x 1.5	24 - 30 mm	5.0 mm	17 mm	Medium (Fuel)
  M14 x 1.5	26 - 32 mm	6.5 mm	19 mm	High (Hydraulic)
  M16 x 1.5	28 - 35 mm	8.0 mm	22 mm	High (Hydraulic)

Galvanizing & Corrosion Resistance

• Ensuring 30+ years of service life in corrosive environments.

• Surface Treatment	Process	Salt Spray Test	Best Application	Fluid Compatibility
  Zinc Plated	Electrolytic	72 - 144 Hours	Indoor Hydraulic	Oil / Fuel
  Zinc-Nickel	High-Alloy	1000+ Hours	Automotive Chassis	Brake Fluid
  SS316 Polished	N/A	1000+ Hours	Marine / Chemical	Corrosive / Food
  Cr6-Free Zinc	Eco-Plating	144 - 240 Hours	General Industrial	Oil / Fuel

Avoid Pitfalls:

• Overtightening Failure: Because these bolts are hollow, they have lower torque limits than solid bolts. We recommend using a torque wrench and referring to our Torque vs. Pressure Charts to prevent shank snapping.

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• Cross-Hole Misalignment: If the side hole isn't centered within the banjo fitting's internal gallery, fluid flow is restricted. Longze ensures the hole position (L2) is within ±0.2mm tolerance for optimal flow.

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• Debris in Gallery: Any metal shavings left inside the hollow gallery can destroy a fuel injector or hydraulic pump. Every Longze banjo bolt undergoes Ultrasonic Cleaning and pressurized air-jet drying before packaging.

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Perfect Fit Assembly:

• Dual Washer Setup: Always use two new Longze Copper or Bonded Washers (one on each side of the banjo fitting) to ensure a high-pressure seal.

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• Matched Banjo Fittings: Ensure the internal diameter of your banjo eye matches the bolt diameter to prevent vibration-induced leaks or flow turbulence.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including computerized leakage simulation, thread gauge verification, and high-pressure burst testing on random samples.

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• Sea-Worthy Packaging: Bolts are packed in plastic-lined 25kg cartons with protective dividers to prevent thread and sealing-face damage during export from our Yongnian hub.

• Q: Can you provide long-neck banjo bolts for double-banjo connections? A: Yes, we manufacture Double Banjo Bolts with two sets of cross-holes to connect two separate fluid lines to a single port.

• Q: Do you offer these in Imperial threads? A: Absolutely. We produce 7/16-20, 1/2-20, and other SAE J514 compliant hollow bolts for North American fuel and brake systems.