Product Description
MC661 – HYDRAULIC BRAKE MASTER CYLINDER (INTERNATIONAL / MEDIUM DUTY TRUCKS)
PART NUMBER(S):
Fleet Products: MC661 (New) | OE: Wagner F661, Raybestos MC661, Dorman M661
DESCRIPTION:
Model: MC661 Hydraulic Brake Master Cylinder
Vehicles: International Harvester medium-duty trucks (1956–1983), select Mack and GM trucks, Diamond T, and Studebaker
• Bore Diameter: 1.50″ (1-1/2″)
• Material: Cast Iron
• Mounting: 3-bolt mount
• Mounting Hole Diameter: 0.413″
• Port Configuration: Dual outlet
• Primary Outlet Thread Size: (2) 1/2-20 UNF
• Reservoir: Included with cap
• Residual Check Valve: Yes
• Brake System: Hydraulic, manual/power assist
• Includes Dust Boot: Yes
Applications:
Is the MC661 right for your International or vintage medium-duty truck? Yes—commonly used in International Harvester trucks (1956–1983) such as CO180, 1654, 1824, S1624, S1823, S1824, and S1853. Also cross-referenced for Mack B42, Diamond T, GM, and Studebaker. Built as a direct OEM replacement with correct bore, ports, and residual valve for reliable hydraulic brake performance.
CROSS-REFERENCE(S):
605-MC661, E-3883, E3883, 270-E3883, 174126, 11119, 1119, E13588007, 602-590, E661, RE661, 661, 8QE214, R4111119, R413883, 48175H, 48175R91, F661, S-4929, S4929, 21973M, M900001, F76151, FE2704, ZJC11119, 01119BXW, BW011119, BW 011119, N4507, 644752, 48175HX, 130328H, 116154H, DX4731, 57836H, 93681R91, DX5454, N2507, 5473006, N1507, 142907H, Dorman M661, Bendix 11119, Centric 130.83002, Coni-Seal MC250430, Wagner F121980, Wagner F661, Wagner MC661, General Motors 5473006, Cardone 10-40661, 10-57586, Studebaker 644752, Delphi MC453, Euclid E-3883, Midland 661, Wagner F1332, F1335, F1343, F1348, F21980, F21985, F21988, F678, Bendix R413883, Meritor R413883, Tru-Torque 661, Autospecialty M94002, BrakeBest MC250430, NMC11240, MCA661, American Reman 83-56002, Certified M661, EIS E661, EIS RE661, Cardone 13-40661, Cardone M661, Dynamic Friction 35571021, ACDelco 174-126, Casting Numbers 616812, FE2704, 2704-C, 29740, 618112, 61A, FD2704, FE2707, S230
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:
✔ Confirm bore size (1.50″) and 3-bolt mount pattern match before installation
✔ Always bench-bleed master cylinder before installing
✔ Inspect brake lines for corrosion and replace if damaged
✔ Ensure residual check valve is present for drum brake systems
✔ Verify correct hydraulic system type (manual or Hydro-Vac) for proper fitment
SUPPORT & ORDERING
For technical support, installation guidance, or to confirm fitment, Call: 1-877-243-0442 | Email: sales@fleet-products.com
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