Description
BA-921 CAT AIR BRAKE COMPRESSOR – C15 / C18 ENGINE (NEW)
PART NUMBER(S):
Fleet Products: 5012533N (New) 5012533X (Reman)| OE: 5012533, 5012533B1, 5012533BXR, 5012533C, 5012533N, 5012533X, 5012533X-C, R9555012533X, 5012532, 5012532X, 5012531, 5012531X, 5011427, 5011427X, 801463, 801465, 801798, 801826, 5014428, 5011441, 5012459, 5012464, 5012510, 5014177, 5014180, 5014235, 5014236, 5014401, 5014402, 5014427, K209254, K209255, K020283, K020284, K020285, K048941, K048942, K048943, K048938, K048939, K048940, K056647, K056649, K056646, K066812, K066832, K066838, K066811, K066831, K066837, K209328, K209329
Caterpillar (CAT):
0R1624, 0R-1624, 10R9375, 10R-9375, 20R0176, 20R0178, 20R-0178, 2233637, 223-3637, 3049991, 304-9991, 3537137, 353-7137, 3850937, 385-0937, 385-0935, 253-1736, 255-4160, 353-7136, 385-0936, 20R-0177, 0R-1623, 223-3636
International:
3861777C91, K041109, K055513, K055514
DESCRIPTION:
Model: BA-921 40 Teeth Compressor WITH External Oil Line
Vehicles: Caterpillar C15, C18 ACERT Engines
• Type: Single-cylinder, single-stage, reciprocating air brake compressor
• Mounting: Flange
• Air Inlet: Top mount
• Air Outlet: Side mount
- Cylinders: 1 358CC
- 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
Applications:
Designed for installation on Caterpillar C15 and C18 diesel engines in heavy-duty truck applications. Also suitable for Detroit Series 60 EGR engines (2002–2006) and other commercial platforms requiring flange-mounted BA-921 configuration compressors. Ideal for fleets operating in vocational, long-haul, or high-demand braking environments. Compatible with air brake systems requiring ST-4 safety valve (not included).
CROSS-REFERENCE(S):
5012533X, 5012533, 10R9375, 5011427, 801463, 5012532, 5012531, K020284, K048943, K066838, OR1624, R9555012533X, 20R0178, 20R0176, 223-3637, 20R0178, 5012533, H5011427X, H5012533X, OR1624, MID5012533X, 170.AC5012533, 745-5012533X, ABP N13AC 20R0178, BC1-25566, BW 5012533X, BX5012533X, CAT 20R-0178, 10R9375, 0R1624, 20R0176, 223-3637, 5011427, 5012531, 5012532, 801463, K020284, K048943, K066838, 385-0935, K020283, R9555012533X
A cross-reference listing means this part should be a suitable replacement for the part numbers listed. Please confirm all 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 CAT 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.
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Warranty Information
