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The main bearing is the foundation upon which the crankshaft rotates, enduring immense forces and ensuring smooth engine operation. The genuine SINOTRUK HOWO 475D-1005054A Main Bearing (Upper) is an OEM‑grade precision component designed to provide a durable, low‑friction surface for the crankshaft main journals. As a critical part of the trusted Sinotruk howo parts family, this upper main bearing guarantees perfect fitment, superior load capacity, and long‑term reliability. Manufactured from high‑strength tri‑metal materials with precision overlay, the 475D‑1005054A unit withstands extreme pressures and temperatures in mining, construction, and long‑haul applications. Investing in this authentic component prevents crankshaft damage, reduces friction, and ensures optimal engine performance and longevity.
Main Bearing(Upper)
Верхний вкладыш коренного подшипника
Cojinete principal (superior)
The 475D-1005054A upper main bearing is constructed from a tri‑metal material system, typically featuring a steel backing for structural rigidity, a copper‑lead or aluminum alloy lining for load carrying, and a soft overlay (often lead‑tin or polymer) for conformability and embedability. This layered construction provides the ideal combination of strength, fatigue resistance, and surface properties necessary to support the crankshaft under extreme combustion pressures. The bearing is precision‑machined to micron‑level tolerances, ensuring consistent wall thickness and proper crush for a secure fit in the main bearing bore.
The upper bearing often incorporates oil grooves and feed holes designed to deliver a continuous supply of pressurized oil to the bearing surface, forming a hydrodynamic film that separates the crankshaft journal from the bearing. This oil film is essential for reducing friction, dissipating heat, and preventing metal‑to‑metal contact. The locking tang (or lug) on the bearing shell precisely locates it within the block and cap, preventing rotation. Each 475D‑1005054A bearing undergoes rigorous inspection for dimensional accuracy, surface finish, and material integrity, guaranteeing reliable performance in the demanding environment of a heavy‑duty diesel engine.
The table below provides detailed technical specifications for the genuine SINOTRUK HOWO 475D-1005054A Main Bearing (Upper). This data is essential for verifying compatibility and understanding the component’s capabilities.
| Parameter | Specification | Details |
|---|---|---|
| OEM Part Number | 475D-1005054A | SINOTRUK HOWO Original Code |
| Product Name | Main Bearing (Upper) | Upper half of main bearing set |
| Material | Steel back with copper‑lead / aluminum alloy lining, polymer overlay | Tri‑metal construction |
| Wall Thickness (mm) | Model‑specific (e.g., 2.5 mm) | Precision ground |
| Width (mm) | Model‑specific (e.g., 40 mm) | Matches main bore width |
| Inside Diameter (finished) | Model‑specific (e.g., 110 mm) | Matches crankshaft journal |
| Oil Groove | Full / partial | Ensures lubrication |
| Oil Hole Diameter | Model‑specific | For oil supply |
| Crush Height | As per design | Ensures proper fit |
| Operating Temperature | Up to 150°C | Withstands engine heat |
| Weight (approx.) | 0.2 kg (per shell) | Light but strong |
| Compatible Engines | SINOTRUK HOWO diesel engines | Verify engine model & main journal size |
Installing main bearings is a precision operation requiring absolute cleanliness and careful measurement. The main bearing bores in the engine block and caps must be clean and within specification. The new 475D-1005054A upper shells are snapped into the block, ensuring the locking tang engages fully. Lower shells (if separate) are installed in the caps. Apply a light coat of assembly lube to the bearing surfaces. The crankshaft is carefully lowered into place. Main bearing caps are installed and torqued to the manufacturer’s specification using the correct sequence and method (torque angle). Bearing clearance must be checked with Plastigage to ensure it falls within service limits.
The 475D-1005054A main bearing is a direct OEM replacement for specific SINOTRUK HOWO engines. Compatibility must be verified by matching the part number with your engine’s model and the required size (standard or undersize). Using the correct bearings ensures proper oil clearance, load distribution, and crankshaft support. Always replace all main bearings as a set. After installation, the crankshaft should rotate freely with minimal resistance. Genuine SINOTRUK HOWO parts guarantee a perfect fit and reliable engine performance.
During installation, ensure the oil holes in the bearings align with the oil passages in the block. Use plenty of assembly lube on all bearing surfaces to prevent dry start damage. Always follow the torque sequence and specifications in the service manual.
The tri‑metal construction of the 475D-1005054A bearing provides exceptional strength to withstand the high peak pressures of turbocharged diesel combustion, preventing fatigue and extending bearing life.
The soft overlay layer embeds small contaminants and provides a low‑friction surface, protecting the crankshaft from scoring and reducing friction during start‑up and boundary lubrication conditions.
The steel backing efficiently conducts heat away from the bearing surface into the engine block and oil, helping to maintain oil film integrity and preventing overheating.
Worn main bearings typically produce a deep, rumbling or knocking noise from the bottom of the engine, especially under load. Low oil pressure, metal particles in the oil, and excessive crankshaft end play are also indicators. During an engine rebuild, bearings should always be replaced. If the crankshaft journals are scored or out of round, they may need to be ground undersize and corresponding undersize bearings used. Visual inspection may reveal flaking, wiping, or scoring of the bearing surface.
Ignoring worn main bearings can lead to catastrophic engine failure, including a spun bearing that can seize the crankshaft or damage the engine block. Replacing them with genuine 475D-1005054A bearings during an overhaul restores proper clearances and ensures reliable engine operation.
Bearing life depends on clean, high‑quality oil and regular changes. Always use the recommended oil viscosity and maintain proper oil pressure. Avoid over‑revving the engine and prolonged idling. Keep the cooling system in good condition to prevent overheating. During major overhauls, always use genuine SINOTRUK HOWO bearings like the 475D‑1005054A.
If the engine has suffered from oil starvation, replace all bearings and inspect the crankshaft for damage. Proper assembly with correct clearances and torque is essential for long bearing life.
Generic aftermarket main bearings may have incorrect material composition, improper crush height, or poor tolerances, leading to early failure and crankshaft damage. The genuine SINOTRUK HOWO 475D-1005054A main bearing (upper) is engineered to the exact specifications of your engine, ensuring correct fit, material properties, and durability. It is manufactured under strict quality controls to withstand the extreme demands of heavy‑duty diesel operation.
By choosing the authentic part, you protect your investment and ensure your engine delivers reliable power for years to come. For engine rebuilders and owner‑operators who demand the best, the genuine 475D‑1005054A is the only responsible choice.
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