Hawk HB803B.639 HPS 5.0 Rear Brake Pads for Ford Mustang GT EcoBoost 2015-23

Vehicle Fitment

• 2015-2023 Ford Mustang EcoBoost / EcoBoost Premium (S550, 2.3L EcoBoost I4, RWD) - Rear, w/ and w/o Performance Package
• 2015-2023 Ford Mustang GT / GT Premium (S550, 5.0L Coyote V8, RWD) - Rear, Manual and Automatic Transmission
• 2015-2017 Ford Mustang V6 / V6 Premium (S550, 3.7L Cyclone V6, RWD) - Rear
• 2015 Ford Mustang GT 50 Years Limited Edition (5.0L Coyote V8, RWD) - Rear
• 2016-2017 Ford Mustang w/ Brembo Package (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, RWD) - Rear

Fitment Notes

• Position: Rear axle only for all applications listed above.
• Not compatible with carbon ceramic rotors. For use with iron/metal rotors only.
• This pad fits the OEM rear caliper of the S550-generation Ford Mustang (2015-2023) across all available engine options and trim levels, including Brembo front brake package variants. The rear caliper is the same regardless of front brake package configuration on these vehicles.
• From the 2021 model year onward, some Hawk database entries note "6 Piston Front Caliper" alongside certain Mustang GT and EcoBoost trim entries. This notation identifies the front brake package variant for reference only - the rear caliper covered by this pad is the same across all 2021-2023 S550 Mustang configurations.
• The 3.7L V6 was available in the S550 Mustang for 2015-2017 only; it was discontinued after the 2017 model year. All 2018-2023 Mustangs use either the 2.3L EcoBoost I4 or the 5.0L V8.
• The Mustang GT 50 Years Limited Edition (2015), Bullitt (2019-2020), and Mach 1 (2021-2023) are special edition variants of the standard Mustang GT platform and share the same rear caliper.
• The EcoBoost Performance Package upgrades the front brakes but uses the same rear caliper - this pad covers all EcoBoost models with and without the Performance Package.
• No electronic wear sensor or hardware is included with this pad set.

Features

• HPS 5.0 (High Performance Street 5.0) Ferro-Carbon compound - The next evolution of Hawk's HPS formula, delivering greater rear stopping power and improved pedal feel compared to the original HPS while maintaining street-appropriate noise, dust, and rotor wear characteristics - the premium rear brake upgrade for S550 Mustang owners who drive their car on public roads and want improved rear brake performance over OEM without race compound trade-offs.
• Designed to work with ABS without triggering ICE mode - The HPS 5.0 compound is precisely tuned to maximize rear brake torque within the operating window of the Mustang's ABS system, improving rear stopping contribution and overall braking balance while maintaining effective ABS engagement on this rear-wheel-drive performance platform.
• Decreased rear stopping distances - Delivers measurably shorter stopping distances when combined with a matched front upgrade, and improves overall braking balance by extracting more performance from the rear caliper's clamping force than standard OEM replacement compounds.
• Improved rear pedal feel throughout the full brake stroke - The HPS 5.0's progressive, linear friction profile provides consistent, informative rear brake response for the precise modulation required when driving the Mustang at spirited pace on public roads.
• Minimal rear brake fade under elevated temperatures - Withstands the heat generated by aggressive street driving, canyon runs, and light autocross use, maintaining consistent rear performance through the elevated thermal conditions that OEM replacement pads approach their limits on this high-powered RWD platform.
• Broader coverage across all S550 variants - The HPS 5.0 is available for the full S550 model range: EcoBoost four-cylinder, V6 (2015-2017), 5.0L V8, and all special editions including the Bullitt, Mach 1, and Brembo Package - making it the single most versatile rear street compound across the entire sixth-generation Mustang lineup.
• Great rear rotor and pad wear life - The Ferro-Carbon formulation balances higher friction output with extended pad and rotor service life, producing less rear disc wear than race compounds while delivering substantially more performance than standard replacement pads.
• Very quiet with low dust output - Operates near-silently with minimal wheel contamination, preserving the premium character of the S550 Mustang's daily-driver persona without the noise and dust of race-class compounds.
• 100% asbestos, lead, chromium, cadmium, and antimony free - Manufactured in an ISO-certified facility to strict quality and environmental standards.

Specifications

• Part Number: HB803B.639
• Compound: HPS 5.0 (High Performance Street 5.0)
• Compound Code: B
• Friction Material: Ferro-Carbon
• Pad Thickness: 0.639 in.
• Total Operating Temperature Range: 100-750°F
• Optimal Temperature Range: 100-550°F
• Position: Rear
• Caliper: OEM Rear Caliper - Ford Mustang S550 2015-2023 (all engines and trim levels)
• Electronic Wear Sensor: Not included
• Hardware: Not included
• Rotor Compatibility: Iron/metal rotors only - not compatible with carbon ceramic rotors
• Recommended Use: Performance Street / Daily Driver / Light Autocross
• Sold as: Set

Included Components

• 2x Hawk HPS 5.0 Rear Brake Pads (HB803B.639)

Product Description

The Hawk HB803B.639 HPS 5.0 rear brake pads fit the OEM rear caliper of the S550-generation Ford Mustang (2015-2023) across every available engine and trim level: the 2.3L EcoBoost I4 (with and without Performance Package), 3.7L V6 (2015-2017), 5.0L Coyote V8 in all GT variants, and all special editions including the GT 50 Years Limited Edition, Bullitt, Mach 1, and Brembo Package configurations. The rear caliper is consistent across all S550 brake packages - front brake upgrades such as the Brembo and Performance Package options do not affect rear caliper fitment.

HPS 5.0 is the natural rear brake upgrade for S550 Mustang owners who drive their car on public roads and want improved rear stopping performance over OEM replacement pads. The compound delivers measurably more rear brake torque than stock replacements, improves pedal feel across the full stroke, and resists fade through the sustained hard braking these performance vehicles regularly encounter in spirited street use - all while maintaining the quiet, low-dust, ABS-compatible characteristics essential for daily driving. The compound is also appropriate for light autocross use where the rear brake temperatures of a single run are well within HPS 5.0's thermal range.

This pad is for the rear axle only. A separate front pad is required for a complete brake upgrade. Compatible with iron and metal rotors only; carbon ceramic brake discs are not supported.