Description
BA-921 DETROIT AIR COMPRESSOR – 1 3/4" INLET, REMANUFACTURED DDC 2007 HDEP — Closed Room Head
PART NUMBER(S):
Fleet Products: K031987X (Remanufactured) | OE: A4721300015, A4721300515, A4721300815, RA4721300815, K020253, K020801, K031986, K031986SC, K031987, K095124, K095740
DESCRIPTION:
Model: BA-921 Twin-Cylinder
Vehicles: Detroit Diesel DDC 2007 HDEP DD13/DD15 (2007 EPA) – Freightliner, Western Star, Cascadia Detroit Diesel DD13/DD15; MBE 900, MERCEDES OM 472, BA921
- Cylinders: 1
- Bore x Stroke: 3.622 in x 2.126 in
- Displacement @1250 RPM: 15.8 CFM
- Flow @1800 RPM /120 PSI: 11.6 CFM
- Flow @3000 RPM /120 PSI: 16.5 CFM
- HP @1800 RPM /120 PSIG: 4.6 HP (loaded) / 0.8 HP (unloaded)
- Min Coolant Flow @Max RPM: 1.5 gpm
- Oil Pressure (min): 15 PSI
- Governor Cut-Out (min): 120 PSI
- Unloader Line: 3/16 in ID
- Temp Range: 170°F inlet / 400°F discharge
Port Sizes & Required Torque
- Cylinder Head (M8): 265–292 in-lb
- Governor Adapter (M8): 195–213 in-lb
- Rear End Cover (M10): 195–213 in-lb
- Inlet Port Fitting (M27x2): 991–1089 in-lb
- Discharge Port Fitting (M22x1.5): 814–912 in-lb
- Water Port Fitting (M18x1.5): 593–637 in-lb
- Oil Port (7/16-16 UNF): 150–170 in-lb
- Unloader Port (1/8-27 NPT): 2–3 turns from finger tight
• Mounting Style: Flange
• Configuration: Engine-driven, thru-drive support
Applications:
Direct replacement for factory-installed compressors on Detroit DD13 and DD15 EPA 2007 engines used in highway tractors, commercial haulers, and heavy-duty vocational trucks. The BA-921 model is ideal for maintaining reliable air supply in brake and auxiliary systems. Commonly used in Freightliner Cascadia and Western Star platforms.
CROSS-REFERENCE(S):
170.ACK031987, 710383AT, A4721300015, A4721300515, A4721300815, HDX K031987X, HDXK031987X, K020253, K020801, K031986, K031986SC, K031987, K095124, K095740
A cross-reference listing means this part should be a suitable replacement for the part numbers listed. Please confirm all ports and dimensions match your application before installing.
IMPORTANT INSTALLATION NOTES:
- Maintain minimum 1.5 gpm coolant flow.
- Ensure external oil supply line is connected for single piston applications.
- Verify air and coolant fittings are properly sealed before startup.
- Drain air reservoirs before servicing air brake components.
- Verify all fasteners are torqued to specification before returning vehicle to service.
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
