4 Hydraulic Pistons + EPB Actuator
Four 28 mm hydraulic pistons drive the pads, paired with a 27 mm EPB actuator piston that retains the factory electronic parking brake.

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Evolution EP4S Rear Wheel 4-Piston Big Brake KitEvolution Series Rear Axle EPB Compatible BBK Evolution EP4S Rear Big Brake Kit with Electronic Parking Brake The Evolution EP4S is a rear axle big brake kit built for modern platforms that still require an electronic parking brake. Four hydraulic service pistons handle stopping work, while a dedicated EPB actuator piston preserves factory parking brake function so you get real rear axle thermal capacity without losing OE convenience. Why Builders
Evolution Series · Rear Axle · EPB-Compatible BBK
The Evolution EP4S is a rear-axle big brake kit built for modern platforms that still require an electronic parking brake. Four hydraulic service pistons handle stopping work, while a dedicated EPB actuator piston preserves factory parking-brake function — so you get real rear-axle thermal capacity without losing OE convenience.
Four 28 mm hydraulic pistons drive the pads, paired with a 27 mm EPB actuator piston that retains the factory electronic parking brake.
The EP4S caliper is machined from a two-piece forged aluminum body for high stiffness at low weight, 4.50 kg per caliper without pads.
Two-piece rotor assemblies with CNC-machined aluminum hats keep unsprung and rotating mass in check while delivering the heat capacity a performance rear axle needs.
Iron rotors are paired with a street/track pad rated 0–600 °C with average μ ≈ 0.38. Carbon-ceramic rotors ship with a CCB-specific pad rated 0–700 °C with average μ ≈ 0.45.
| Brake Caliper | ||
|---|---|---|
| Series | Evolution Series | |
| Model / Application | EP4S | |
| Axle Position | Rear | |
| Piston Count | 4 hydraulic + 1 EPB actuator | |
| Piston Type | Two-piece heat-insulated, dust boots + EPB actuator | |
| Piston Diameter | 28 mm × 4 / 27 mm × 1 | |
| Total Piston Area | 30.4 cm² per caliper | |
| Caliper Dimensions | 278 × 202 × 93 mm (L×W×H) | |
| Manufacturing Process | Two-piece forged aluminum body | |
| Net Weight | 4.50 kg per caliper (no pads) | |
| Surface Finish | High-temperature gloss coating | |
| Recommended Wheel Size | 18 in or larger | |
| Recommended Rotor Size | Ø345–380 mm × 28 mm | |
| Brake Rotor Options | ||
| Rotor Option | Iron Rotor | Carbon-Ceramic Rotor |
| Rotor Material | Heat-treated high-carbon iron | Carbon-ceramic composite |
| Axle Position | Rear | Rear |
| Rotor Dimensions | Ø345 / 355 / 380 × 28 mm | Ø380 × 28 mm |
| Construction | Two-piece, internally vented | Two-piece, internally vented |
| Rotor Mounting | Fixed or floating, size/application dependent | Floating |
| Directional Design | Yes — left/right specific | Yes — left/right specific |
| Rotor Face Pattern | Curved slot / Grain slot / Wave slot / Drilled & slotted | Cross-drilled |
| Brake Pad Options | ||
| Pad Option | Iron Rotor Pad | CCB Rotor Pad |
| Compatible Rotor Material | Iron rotors only | Carbon-ceramic rotors only |
| Operating Temperature Range | 0–600 °C | 0–700 °C |
| Average Friction Coefficient | avg μ ≈ 0.38 | avg μ ≈ 0.45 |
| Lines | ||
| Brake Line Construction | Three-layer reinforced | |
| Brake Line Material | PTFE liner / SUS304 braid / PVC outer sheath | |
| Brake Line Fittings | Vehicle-specific fittings | |
| Brackets | ||
| Rotor Hat Manufacturing Process | CNC-machined | |
| Rotor Hat Material | High-strength aluminum alloy | |
| Caliper Bracket Manufacturing Process | CNC-machined | |
| Caliper Bracket Material | Carbon steel | |
| Caliper Mounting Type | Radial mount with vehicle-specific brackets | |
| Fitment & Installation | ||
| Minimum Spoke Clearance | 97 mm | |
| Recommended Wheel Size | 18 in or larger | |
| EPB Interface | Vehicle-specific; final EPB interface details vary by application | |
| Bedding-In Procedure | Required before aggressive use | |
Iron rotors are paired with a street/track pad rated 0–600 °C with average μ ≈ 0.38. Carbon-ceramic rotors ship with a CCB-specific pad rated 0–700 °C with average μ ≈ 0.45 — strong initial bite with linear modulation deeper into the pedal.
2× EP4S 4-piston rear calipers with integrated EPB actuator.
Performance brake pads matched to rotor material for both calipers.
2× two-piece rotors in your selected size and face pattern.
CNC carbon-steel mounting brackets.
CNC aluminum rotor hats.
Stainless-steel braided brake lines with vehicle-specific fittings.
Mounting hardware is included.
This is a platform-adapted rear big brake kit. Final brackets, brake-line fittings, rotor diameter, and EPB interface details vary by vehicle and must be confirmed before ordering.
18-inch wheels or larger are required.
Minimum spoke clearance is 97 mm. Verify your wheel offset and internal spoke geometry before purchase.
Brackets, brake-line fittings, rotor size, and EPB interface are confirmed per application.
Contact us with your year/make/model/trim and wheel spec so we can validate fitment before you order.
Yes. The caliper includes a dedicated EPB actuator piston (27 mm) in addition to the four hydraulic service pistons, so the OE electronic parking brake function is retained when correctly interfaced with your vehicle.
Iron rotors are offered in Ø345, 355, and 380 mm × 28 mm. A carbon-ceramic composite option is available in Ø380 × 28 mm. All are two-piece, internally vented, and directional (left/right specific).
18 inches or larger, with a minimum 97 mm spoke clearance. Wheel internal geometry varies even within the same diameter — confirm clearance against the caliper envelope (278 × 202 × 93 mm) before ordering.
The EP4S is a platform-adapted kit. Brackets, brake-line fittings, rotor size, and EPB interface are confirmed per application. Contact us with your year/make/model/trim and wheel spec so we can validate fitment before you order.
It replaces a smaller OE rear caliper and rotor with a stiffer four-piston forged caliper and a larger two-piece vented rotor. The result is greater thermal capacity, more consistent rear-axle contribution, and more stable pedal feel under repeated heavy stops.
Iron rotors ship with a 0–600 °C street/track pad (avg μ ≈ 0.38). Carbon-ceramic rotors ship with a CCB-specific pad rated 0–700 °C (avg μ ≈ 0.45). Both are matched to the rotor material and should never be cross-used.
Need fitment confirmation, a custom rotor face pattern, or a matched front big brake kit?