The Hawk HB642F.658 is a rear pad in Hawk's HPS (High Performance Street) line, built for street-legal cars that see spirited driving. The manufacturer positions it as a step up from OE pads, citing stronger stopping power, firmer pedal feel, higher thermal capability, and less dust. A B8 A4 or S4 that sees mountain roads or repeated hard stops gets a more confident braking response than stock pads deliver, without moving to a full race compound. Cheaper pads may cost less up front, but they rarely target the same balance of bite, pedal control, and heat tolerance.
Hawk's fitment list covers a range of 2009 to 2017 Audi models, including A4, A5, S4, S5, Q5, SQ5, and allroad versions on the B8 and 8R platforms. Because the product title references the 09-10 A4, confirm your VIN with the manufacturer before ordering. On B8 cars the rear calipers use an electric parking brake, and owners on user forums report that the piston must be wound back with a scan tool or a special retraction procedure before the pads go in. Skipping that step can leave the brake warning light on. Plan for jack stands, Torx and metric sockets, a piston retraction tool, and brake cleaner. Searches for HB642F.658 rear pads, Hawk HPS B8 A4 pads, and B8 S4 rear HPS upgrade will lead buyers to this listing.
No. The manufacturer states that Hawk HPS compounds are not compatible with carbon ceramic rotors and are designed to work with iron or metal rotors.
Owners on user forums report that the B8 electric parking brake must be retracted with a scan tool or a special procedure before the rear pads are replaced. Confirm the correct method for your model year before starting.
The manufacturer lists fitment across multiple 2009 to 2017 Audi models and submodels, so fitment depends on your exact model, engine, and year. Check your VIN with the manufacturer before ordering.
This is a moderate-difficulty job for a home mechanic with basic tools, but the B8 rear electric parking brake adds a step that standard pad swaps do not require. Owners on user forums recommend retracting the rear pistons correctly before fitting the new pads, and to avoid pressing the brake pedal with the caliper removed. Use a scan tool or a proper retraction procedure, reinstall the caliper, then pump the pedal until it feels firm before driving. Verify the parking brake and brake warning light after the job is complete.
