Hawk HB803F.639 HPS Rear Brake Pads 2015-2023 Ford Mustang GT/EcoBoost/Mach 1

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).
• Brembo Package (front) Mustangs (2016-2017 and optional on later years) use the same rear caliper as non-Brembo models - this pad fits all S550 rear brake configurations.
• Does not fit the Shelby GT350, GT350R, GT500, or any Shelby model, which use a different rear caliper and pad shape.
• Not compatible with carbon ceramic rotors; designed for iron/metal rotors only.
• Street use only - HPS can withstand light track use but is not a sustained race compound.
• No electronic wear sensor or hardware included.

Features

• HPS Ferro-Carbon compound delivers 20-40% more stopping power than OEM replacement pads - a well-rounded upgrade that improves rear braking confidence across the S550 Mustang's full model range from EcoBoost to Mach 1.
• Higher coefficient of friction both hot and cold - confident, progressive rear bite from the first application with no warm-up required.
• Fade-resistant up to 700°F - effective across spirited street driving, canyon runs, and occasional track or autocross use.
• Smooth, predictable pedal feel and consistent brake release characteristics matched to the S550's independent rear suspension and stability management systems.
• Gentle on rotors with extended pad and rotor service life compared to HP Plus or race compounds.
• Virtually noise-free with low dust output - a premium street upgrade that retains the refinement expected in a daily-driven Mustang.
• Backed by Hawk's limited lifetime warranty against manufacturing defects.

Specifications

• Part Number: HB803F.639
• Compound: HPS - High Performance Street (F)
• Pad Thickness: 0.639 in.
• Position: Rear
• Caliper Type: OEM
• Platform: Ford Mustang S550 (2015-2023)
• Material: Ferro-Carbon
• Operating Temperature Range: 100-700°F
• Optimal Temperature Range: 100-500°F
• Construction: Integrally molded
• Electronic Wear Sensor: No
• Hardware Included: No

Included Components

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

Product Description

The Hawk HB803F.639 HPS rear brake pads are engineered for the rear axle of the 2015-2023 Ford Mustang S550 across all trims and powertrains - V6, EcoBoost, GT, Bullitt, and Mach 1. The S550's rear caliper is shared across the entire model range regardless of front brake package, making this a single solution for Mustang owners who want improved rear braking performance without sacrificing the street-friendly character of the HPS compound. From the base EcoBoost to the high-revving Mach 1, the HPS delivers 20-40% more stopping power over OEM replacement pads with better fade resistance and a quieter, cleaner brake system.

For S550 owners who use their Mustang primarily on the street with occasional autocross or track day outings, the HPS provides the right balance of performance and usability - effective from cold for the morning commute, fade-resistant for a spirited weekend drive, and capable of handling light track sessions without requiring pad changes. Mustang GT owners who want more performance for regular track use should consider the HP Plus (HB803N.639) or HPS 5.0 (HB803B.639) variants on this same pad shape. A proper bed-in procedure is recommended after installation.