Centric 320.66018F Disc Brake Rotor - Front or Rear

Centric GCX Rear Rotor for Heavy-Duty Applications

The Centric GCX Elemental Protection Disc Brake Rotor, part number 320.66018F, is a rear vented rotor built for Chevrolet P30 and GMC P3500 applications. It features a fully coated disc finish, coated hat, and smooth surface to support corrosion resistance and consistent braking performance in demanding service.

Key Features

• Fits 1975-1996 Chevrolet P30, rear
• Fits 1979-1996 GMC P3500, rear
• Part number 320.66018F for direct application lookup
• Fully coated disc finish with coated hat finish
• Vented rotor design with straight vane style
• Smooth surface type for brake pad contact
• Outside diameter: 13.740 in. / 349.000 mm
• Nominal thickness: 1.535 in. / 39.000 mm
• Discard thickness: 1.465 in. / 37.210 mm
• Center hole diameter: 5.504 in. / 139.800 mm
• 10 mounting bolt holes with 7.248 in. bolt circle diameter
• Disc mounting behind the hub

Product Details

Centric GCX Elemental Protection Disc Brake Rotors are part of Centric’s full-coating rotor line, which focuses on protecting exposed metal surfaces from corrosion while maintaining a service-ready braking surface. This rear rotor is engineered with a vented construction, straight vanes, and a smooth face to support stable heat management and predictable pad contact on Chevrolet P30 and GMC P3500 rear brake systems. The 320.66018F rotor measures 13.740 inches in outside diameter and uses a 10-hole bolt pattern with behind-the-hub mounting.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Common Brake Issues It Can Address

• Rear brake rotor corrosion on exposed braking surfaces and hat areas
• Brake pulsation caused by worn or uneven rotor thickness
• Reduced braking consistency from heat-affected rotor surfaces
• Noise or vibration linked to rotor wear beyond discard thickness
• Fitment problems when replacing a rear rotor on Chevrolet P30 or GMC P3500 platforms

Installation Notes and Tips

Verify rotor dimensions, bolt pattern, center hole diameter, and rear position before installation. Clean the hub mounting surface thoroughly so the rotor seats flat behind the hub, and inspect pads, calipers, and hardware condition during service. Measure rotor thickness after installation to confirm it remains within specification for the brake system.

Quality Assurance

Centric GCX rotors are built with coated surfaces to help resist corrosion on the disc and hat areas, supporting long-term service in commercial and heavy-duty brake applications. Part number 320.66018F is specified for rear fitment on 1975-1996 Chevrolet P30 and 1979-1996 GMC P3500 models.