Brake Master Cylinder 1 1/8″ Bore Dual Port – Replacement for Chevy/GMC Trucks and Heavy-Duty Industrial Vehicles (M8716721)

ABC Dynamics: Precision Parts for Uncompromising Performance.

Restore superior hydraulic control to your braking system with this brand-new, high-quality **M8716721 Master Cylinder**. Engineered for **heavy-duty applications**, this dual-port unit features a robust **1 1/8″ bore** and is a confirmed replacement for the **3769215** and **29786C** casting numbers. It is an ideal component for **classic Chevy/GMC trucks** and various types of **industrial equipment**, ensuring reliable, consistent stopping power you can trust.

Key Specifications & Expert Features

• Bore Size: **1 1/8″ bore** (1.125″) for optimal fluid displacement in large caliper/wheel cylinder systems.
• Port Configuration: **Dual ports** for effective hydraulic distribution to front and rear circuits.
• Line Thread Size: **7/16″-24 thread** at the 6 o’clock position (Critical for line connection verification).
• **Robust Construction:** Built new to meet or exceed OEM specifications for lasting durability in high-demand **vehicle** use.
• Repair Kit Compatibility: Compatible with repair kit **253MK** for easy maintenance.

Verified Casting & Part Numbers (Cross-Reference)

This Brake Master Cylinder is a confirmed replacement for the following casting and part numbers, commonly found on **Chevrolet/GMC trucks** and other **industrial/commercial vehicles**. Matching your existing number is the **most reliable method** to ensure correct fitment:

• 3769215, 3769216
• 29786C, 29788C

Expert Note: Thread Verification and Installation

Experience Tip: Due to the variety of fittings used on trucks and equipment of this vintage, it is vital to confirm the **7/16″-24 thread size**. If your line threads differ, you may need an adapter, but always confirm the **1 1/8″ bore size** first, as this is non-negotiable for correct brake balance and pedal feel in your **vehicle**.