Description
CUMMINS ISX / X15 ENGINE AIR COMPRESSOR (85MM, SINGLE CYLINDER)
PART NUMBER(S):
Fleet Products: 9121400520X (Remanufactured) | OE: WABCO 9121400520, 9121400120, CUMMINS 5558790, 4337585, 5558790, 5633492RX, 5273898, 5558790, 5633492, 9121400120, 9121400520, 9121400520R, 9121400527, 9121400530
DESCRIPTION:
Model: 9121400520 (WABCO 85mm Single-Cylinder Air Compressor) 35 Teeth Gear drive
Vehicles: Cummins ISX12, ISX15, X15, QSX Engines (2010–2025)
• Bore: 85 mm
• Stroke: 56 mm
• Swept Volume: 318 cm³
• Max Operating Pressure: 10.0 bar
• Operating Speed: 3000 RPM
• Lubrication: Supplied from Engine
• Port Threads:
– Inlet M30 x 1.5
– Discharge M26 x 1.5
– Governor M10 x 1.0
– Drain 1/8"-27 NPTF
– Coolant M16 x 1.5
Applications:
Is this air compressor compatible with your Cummins-powered heavy-duty truck? Yes—designed for ISX, X12, and X15 engines from 2010–2025, this 85mm WABCO compressor delivers OEM-grade air pressure and durability. It’s built to maintain stable brake system performance under continuous duty cycles, ensuring reliable air delivery for braking and auxiliary systems across long-haul and vocational fleets. NOTE: THIS COMPRESSOR COMES WITH 35 TEETH GEAR. 9111530270X and 9111530197X has 31 Teeth Gear.
CROSS-REFERENCE(S):
5558790, 9121400520, 9121400120, 5273898, 81600560, 2T2100759B, 3999917, 701497AT, KGM55450
A cross-reference listing means this part is a suitable replacement for the part numbers listed. Please confirm all ports and dimensions match your application before installing.
IMPORTANT INSTALLATION NOTES:
✔ Prime the lubrication system before initial start-up to prevent dry start damage.
✔ Verify port thread sizes and coolant connections match engine configuration before mounting.
✔ Torque mounting bolts to manufacturer specification and check for air and coolant leaks after installation.
✔ Always pair with a properly functioning air dryer to prevent moisture damage to the compressor.
SOLD AS REMANUFACTURED – CORE RETURN REQUIRED
Built to OEM standards — thoroughly cleaned, inspected, and tested to ensure durability, performance, and reliability in demanding applications.
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Warranty Information
