Wilwood Street Performance AERO4 BB Rear P-Brake Kits, Drilled, Red For Big Ford, 2.36 Offset, 14.00 Rotor

The Wilwood AERO4 Big Brake Rear Axle Kit (Part #140-10947-DR) is designed for high-performance applications requiring greater rear brake capacity and control, especially when paired with front big brake kits. It replaces the factory rear disc brakes while maintaining compatibility with the original equipment (OE) parking brake assembly, master cylinder, ABS, and brake bias. Technical upgrades include large 14-inch drilled and vented rotors for improved heat dissipation, robust BP-20 compound pads for better friction and stopping consistency, and Wilwood AERO4 4-piston callipers for even, reliable clamping force. The kit also features precision-machined adapters, a multi-pattern hat compatible with common Ford bolt circles, and shims for precise alignment. All hardware, brackets, calliper mounts, and a bearing retainer are included. The system works with the original internal drum parking brake design and matches the requirements of Big Ford rear axles, optimising brake performance with upgraded wheels and tyres.

KEY SPECS AT A GLANCE

- Part Number: 140-10947-DR (drilled rotor option)
- Rotor: 14.00" diameter, 1.10" thick, vented, drilled, and black finished
- Rotor offset: 2.36"
- Caliper: Wilwood AERO4, 4 piston, radial mount (red finish optional)
- Pad compound: BP-20
- Mounting: Fits 5 x 4.50", 4.75", and 5.00" bolt patterns (12 x 8.75” BC)
- Max axle flange diameter: 6.61" with chamfer
- Wheel stud size required: 0.50" diameter
- Minimum wheel clearance to caliper: 0.080" in all directions
- Compatible with OE parking brake assembly
- Includes brackets, mounting hardware, spacers, and bearing retainer.

WHAT TO EXPECT DURING INSTALLATION

Mechanical experience is needed for installing this kit, as removal of the stock brakes down to the bare axle is required. Key steps include verifying axle flange patterns and offsets, removing original bearing retainers, and ensuring all parts fit and clear before final assembly. Proper torque specs and the use of thread locker are important for assembly, and shims are included for accurate calliper alignment. The kit does not include hydraulic lines, parking brake cables, or adapters; these may need to be sourced separately, depending on your vehicle. After assembly, carefully bleed the brakes, adjust the parking brake, and perform bedding procedures to ensure optimal performance. Regular inspection of the brake system is recommended after installation.

NOTES ON FACTORY FIT AND COMPATIBILITY

- Designed specifically for Big Bearing Ford rear axles
- Axle flange offset must be 2.36", and axle flange diameter cannot exceed 6.61" (with chamfer)
- Supports 5 x 4.50", 4.75", and 5.00" bolt patterns on a 12 x 8.75" circle
- Supplied hardware may not be compatible with every axle—installer must confirm fit
- Brake lines, cables, and adapters are not included and may be required
- Ensure at least 0.080" clearance between the calliper and wheel in all areas
- Some vehicles may need shock modification/relocation for proper clearance
- Always verify the axle flange and housing pattern before installation.