61021401 Hollow Screw – Engineering, Function & Applications

The 61021401 Hollow Screw is a specialized banjo bolt designed for fluid transfer in SANY heavy equipment. Unlike a standard solid bolt, a hollow screw has a central axial drilling from the head down to a point just above the thread end, plus one or more radial cross‑holes near the tip. When the bolt is tightened into a threaded port, fluid enters the cross‑holes, flows up the axial passage, and exits through a connected banjo fitting or directly into a component gallery. This design allows compact, right‑angle fluid connections without external hoses or elbow fittings.

The 61021401 hollow screw is manufactured from high‑strength alloy steel (typically property class 10.9 or 12.9) and heat‑treated for tensile strength. The thread is metric M10×1.5 with a 6g tolerance. The head is a hexagon socket (Allen) type, allowing installation in confined spaces using a hex key. The bolt is zinc‑plated with yellow passivation for corrosion resistance, and the drilled passages are deburred to ensure smooth fluid flow and prevent debris entrapment.

Common applications of the 61021401 hollow screw in SANY D12 and D09 engines include the turbocharger oil supply banjo fitting, the fuel injection pump inlet banjo bolt, the high‑pressure fuel return line banjo connections, and the engine oil cooler line attachments. In hydraulic systems, it is used for pilot pressure supply lines and hydraulic pump case drain connections. The banjo bolt is always used together with two copper seal washers (61021400) – one under the bolt head and one under the banjo fitting – to create a leak‑proof seal.

Applications & Fluid Systems Using 61021401 Hollow Screw

The 61021401 Hollow Screw is used in multiple fluid systems across SANY heavy equipment. In the engine lubrication system, it serves as the banjo bolt for the turbocharger oil supply line on D12 and D09 engines. In the fuel system, it is used at the inlet and return ports of the injection pump and on the fuel filter head. In the cooling system, some cylinder head coolant passages use hollow screws for coolant distribution. In hydraulic systems, pilot control valve supply lines often employ banjo bolts for compact routing.

SANY equipment that commonly uses this part includes SKT90, SKT90S, SKT80 dump trucks; SY395, SY500 excavators; SW series wheel loaders; STC cranes; and concrete pump trucks. In each application, the 61021401 hollow screw works in conjunction with two copper seal washers (61021400) and a banjo fitting. The assembly is torqued to 25‑30 N·m, which crushes the copper washers to create a leak‑tight metal seal.

Technical Specifications: 61021401 Hollow Screw (Banjo Bolt)

Failure Modes & Warning Signs for the Hollow Screw

The 61021401 Hollow Screw is a robust component, but failures can occur due to over‑torquing (stripping threads or cracking the head), under‑torquing (leakage past the seal washers), or cross‑threading during installation. Corrosion can also occur if the zinc plating is damaged, leading to thread seizure. The drilled passages can become blocked by debris or carbon buildup, especially in turbocharger oil supply lines, causing oil starvation and turbo failure.

Warning signs include visible fluid leakage around the banjo fitting, engine oil or fuel odor, low oil pressure (from a restricted supply line), or black smoke from the exhaust (fuel system leakage). If the hollow screw is stripped, it must be replaced immediately; do not attempt to retap the hole or use thread‑repair inserts without consulting SANY engineering.

Installation & Torque Guidelines for 61021401

Proper installation of the 61021401 Hollow Screw is critical for leak‑free operation. Always use new copper seal washers (61021400). Clean the threaded port and the banjo fitting mating surfaces. Place one copper washer on the bolt, then insert the banjo fitting, then the second copper washer, then tighten by hand. Using a torque wrench and an 8 mm hex bit, torque the bolt to 25‑30 N·m. Do not exceed 35 N·m, as over‑torquing can crush the washers too much or stretch the bolt.

After installation, start the engine and check for any leaks. If a small seepage is observed, you may attempt to re‑torque to the upper limit (30 N·m). If leaks persist, inspect the washers and the sealing faces for damage. Never reuse a hollow screw that has been over‑torqued, as the threads may have yielded. Always use genuine SANY parts for replacement.

Why Choose Genuine SANY 61021401 vs. Aftermarket

Preventive Maintenance & Replacement Interval

The 61021401 Hollow Screw itself is not a wear item and can last the life of the equipment if properly installed and never over‑torqued. However, the copper seal washers (61021400) must be replaced every time the bolt is loosened. The bolt should also be replaced if its threads are damaged or if it shows signs of corrosion pitting. It is good practice to replace the hollow screw whenever you rebuild a component (e.g., turbocharger, injection pump) because the bolt may have accumulated stress from repeated tightening cycles.

Fleet operators should keep a small stock of 61021401 hollow screws along with matching seal washers. These fasteners are inexpensive, and having them on hand prevents delays during emergency repairs. When servicing a SANY engine, always inspect the hollow screw for any sign of cracking around the cross‑hole area – this is a high‑stress zone and any crack warrants immediate replacement.

The Critical Role of Hollow Screws in Fluid System Integrity

The 61021401 Hollow Screw is a small but vital component that enables compact, efficient fluid routing in SANY heavy equipment. Without it, many banjo connections would require bulky adapters or additional hoses, increasing weight and potential leak points. Its ability to carry high‑pressure fluids (up to 300 bar in fuel systems) while withstanding engine vibration and thermal cycling is a testament to SANY’s engineering excellence.

When a hollow screw fails – whether by cracking, leaking, or becoming blocked – the consequences can range from a small fluid drip to a catastrophic fire or engine seizure. Therefore, using genuine SANY parts is not just a matter of quality but of safety. The 61021401 hollow screw has been validated through thousands of hours of field testing in SANY machines, ensuring that it meets the exacting demands of mining, construction, and heavy transport.

For your next repair or maintenance job on a SANY truck or excavator, insist on the original 61021401 Hollow Screw. It is a small investment that protects your equipment, your operators, and your bottom line. Trust genuine SANY parts – engineered to work together, built to last.