The part number A0280748802 to correspond to a unit pump for the Mercedes-Benz MBE900 series of engines. The MBE900 is a common heavy-duty diesel engine used in trucks and industrial applications.

Key Details:

• Application: Mercedes-Benz MBE900 (also used in some Freightliner and Detroit Diesel applications).

• Function: The unit pump is part of the fuel injection system, delivering high-pressure fuel to the injectors.

• Compatibility: Verify with your engine’s exact model and serial number, as variations exist.

Alternative/OEM Cross-References:

• OEM Numbers:

• Mercedes-Benz: 0280748802 (without the “A” prefix)

• Detroit Diesel: 23518434 (possible equivalent)

The unit pump is a mechanically actuated, high-pressure fuel pump that works with the engine’s electronic control system (ECU) to deliver precise fuel amounts to each cylinder.

• a. Housing & Material Construction

• Material: Typically made from high-strength alloy steel or forged steel to withstand extreme pressures (up to 1,800–2,200 bar in some systems).

• Precision Machining: Critical surfaces (e.g., plunger bore, cam follower) are hardened and ground for durability and smooth operation.

• Sealing: Uses high-pressure O-rings and gaskets to prevent fuel leaks.

• b. Internal Components

• Plunger & Barrel Assembly:

• The plunger is driven by the engine’s camshaft via a roller tappet.

• Precision-matched to ensure minimal fuel leakage and maximum pressure buildup.

• Solenoid Valve (if electronically controlled):

• Regulates fuel delivery timing and quantity based on ECU signals.

• Return Spring:

• Ensures the plunger resets after each stroke.

• c. Fuel Inlet/Outlet Ports

• Low-pressure inlet: Receives fuel from the supply pump.

• High-pressure outlet: Delivers fuel to the injector via a high-pressure line.

• 2. Strengths & Advantages

• The MBE900 unit pump is designed for reliability, efficiency, and performance in heavy-duty applications.

• a. High Durability

• Robust construction resists wear from continuous high-pressure operation.

• Hardened components (e.g., cam follower, plunger) extend service life.

• b. Precision Fuel Delivery

• Mechanical/electronic control ensures accurate metering for optimal combustion.

• Consistent pressure output improves engine efficiency and reduces emissions.

• c. Simplified Maintenance

• Modular design allows individual replacement (unlike unit injectors, which are more integrated).

• Easier troubleshooting compared to common-rail systems in some cases.

• d. Compatibility & Adaptability

• Works with different MBE900 variants (e.g., 4.8L, 7.2L, 8.3L).

• Used in Mercedes-Benz, Freightliner, and Detroit Diesel applications.