Hawk HB803N.639 HP Plus Rear Brake Pads 2015-2023 Ford Mustang GT/EcoBoost

Vehicle Fitment

• 2015-2023 Ford Mustang EcoBoost / EcoBoost Premium (2.3L EcoBoost I4, RWD) - Rear, all brake packages
• 2015-2023 Ford Mustang EcoBoost Performance Package (2.3L EcoBoost I4, RWD) - Rear
• 2015-2018 Ford Mustang V6 (3.7L V6, RWD) - Rear
• 2015-2023 Ford Mustang GT / GT Premium (5.0L Coyote V8, RWD) - Rear, all brake packages incl. Brembo
• 2015 Ford Mustang GT 50 Years Limited Edition (5.0L Coyote V8, RWD) - Rear
• 2019-2020 Ford Mustang Bullitt (5.0L Coyote V8, RWD) - Rear
• 2021-2023 Ford Mustang Mach 1 (5.0L Coyote V8 High-Revving, RWD) - Rear

Fitment Notes

• Rear axle application only - OEM caliper, 0.639 in. pad thickness.
• Covers all S550-generation Mustang (2015-2023) rear caliper configurations - the rear brake system is shared across all S550 trims regardless of front brake package (standard, Performance Package, or Brembo 6-piston).
• Does not fit the Shelby GT350, GT350R, GT500, or any Shelby model, which use a different rear caliper and pad shape.
• Suitable for autocross, HPDE, spirited street driving, and track days - still drivable on the street after track use without requiring pad changes.
• Expect increased dust, noise, and rotor wear compared to HPS or OEM pads.
• Not compatible with carbon ceramic rotors; designed for iron/metal rotors only.
• No electronic wear sensor or hardware included.

Features

• HP Plus Ferro-Carbon compound delivers the highest friction levels available in a rear pad that remains streetable - the ideal upgrade for S550 Mustang owners who regularly attend autocross events, HPDE sessions, or track days.
• Significantly higher coefficient of friction over HPS - more aggressive rear bite for faster deceleration rates and improved brake balance under hard track braking.
• Wide operating temperature range of 100-800°F with an optimal window of 100-600°F - effective from a cold street start through sustained hard braking on circuit.
• Fade-resistant across consecutive heavy rear stops - meaningful improvement over HPS for drivers who push the S550 hard in high-speed environments.
• Still drivable on the street after a track day without pad changes - no dedicated warm-up requirement from cold.
• Backed by Hawk's limited lifetime warranty against manufacturing defects.

Specifications

• Part Number: HB803N.639
• Compound: HP Plus (N)
• Pad Thickness: 0.639 in.
• Position: Rear
• Caliper Type: OEM
• Platform: Ford Mustang S550 (2015-2023)
• Material: Ferro-Carbon
• Operating Temperature Range: 100-800°F
• Optimal Temperature Range: 100-600°F
• Construction: Integrally molded
• Electronic Wear Sensor: No
• Hardware Included: No

Included Components

• 2x HP Plus Brake Pads (Rear Axle Set - Driver and Passenger Side)

Product Description

The Hawk HB803N.639 HP Plus rear brake pads are engineered for the rear axle of the 2015-2023 Ford Mustang S550 across all trims - EcoBoost, V6, GT, Bullitt, and Mach 1 - sharing the same rear caliper interface as the HPS (HB803F.639) and HPS 5.0 (HB803B.639) variants. For S550 owners who regularly compete in autocross or attend track days and have found the HPS compound fading or lacking sufficient rear bite under sustained use, the HP Plus delivers the maximum friction output available in a rear pad that can be driven home after the event.

The HP Plus's wide effective temperature range, starting from cold through an 800°F ceiling, provides confident rear braking from the very first stop while building into its full performance potential as temperatures rise during a track session. Compared to the HPS on the same pad shape, the HP Plus trades some quietness and reduced dust for significantly more rear brake torque - the right choice for competitive S550 drivers who want to maximize the independent rear suspension's braking performance without committing to a pure race compound. A proper bed-in procedure is required after installation to achieve optimal performance.