10.8 - Brakes¶

Type: Four-wheel disc, electro-hydraulic boost

Calipers and Rotors: Factory Ford Super Duty, four corners

Pads and Rotors: PowerStop Z36 Truck & Tow, front and rear

Booster: Bosch Gen 2 iBooster (see Brake Booster)

Master Cylinder: Wilwood Tandem Compact, 1-1/8" bore

Park Brake: Factory drum-in-hat, mechanical lever

ABS: None. Tone rings and wheel speed sensors omitted at both axles.

Axle-side brake hardware and system sizing for the Super Duty axles. The booster, master cylinder mounting, adapter, harness, firewall plate, and plumbing are documented on the Brake Booster page.

Calipers and Rotors¶

Corner	Hardware
Front	Factory Super Duty caliper and rotor (Front Axle, Dana 60)
Rear	Factory Super Duty caliper and rotor with drum-in-hat park brake (Rear Axle, Sterling 10.5)
Pads and Rotors	PowerStop Z36 Truck & Tow kit, front and rear, 2005-2007 F-250/F-350 SRW application¹

Kit Year Range

The Z36 kit application is listed as 2005-2007. The donor axles can be 2005-2010. Match the kit to the donor axle years before ordering.

Booster and Master Cylinder¶

Specification	Value
Booster	Bosch Gen 2 iBooster, direct mechanical pushrod, M8x1.25¹
Pedal Ratio	Approximately 4:1; verification TBD #301
Master Cylinder	Wilwood Tandem Compact, 1-1/8" bore²
MC Adapter	Back Bay Customs (see Brake Booster)
Harness	TBD #105 — Tulay's Gen 2 or EVcreate kit (see Brake Booster)
Firewall Plate	60x80mm pattern (see Brake Booster)

Master Cylinder Sizing

The 1-1/8" bore is sized for knockback margin with the Super Duty calipers, not steady-state caliper volume. It supersedes the 1.00" bore chosen for the TJ Rubicon calipers.²

Park Brake¶

Factory drum-in-hat in the rear rotors, mechanical lever. Cables built at full droop.¹

Lines and Proportioning¶

Braided flex hoses at each axle, measured at full droop (TBD #86); plumbing on the Brake Booster page
Adjustable proportioning valve on the rear circuit (TBD #60). With no ABS this valve is the only rear lockup control, so set it on a low-grip surface rather than by the bias figure alone
Front/rear bias starting point approximately 62/38¹

Outstanding Items¶

🔴 Critical (1)

Rear 5.13 long-spline gearset (Revolution F10.25-513L) sourcing confirmation (#297) — There is no 10.5-native 5.13; the rear Sterling 10.5 runs the Revolution F10.25-513L (Ford 10.25" long pinion) with master kit 35-2046. Confirm availability and lead time with Revolution or a dealer before ordering the kit. A 2008-2010 donor housing also needs the SK F10.5-Conv pinion spacer (sold separately).

High (8)

Re-spec 8HP70 → NP241OR adapter path (case changed from JK NV241 to TJ Rubicon Rock-Trac) (#313) — The transfer case selection changed from the JK NV241 GenII Command-Trac (2.72:1) to the TJ/LJ Rubicon NP241OR Rock-Trac (4:1) (owner decision, 2026-09-18 — deeper low range). All the adapter research on the transfer-case page was done against the JK case and does not carry over automatically.
iBooster pedal ratio verification against 1.25" booster stroke (#301) — Verify the brake pedal ratio (approximately 4:1 per owner notes, 03-06 TJ/LJ auto pedal) against the Bosch Gen 2 iBooster's 1.25" stroke so the pedal reaches full booster travel without the cylinder bottoming, with the 1-1/8" Wilwood master and Super Duty calipers at all four corners. Bench-measure on assembly.
ARB RD140 fitment with Revolution F10.25-513L in the Sterling 10.5 housing (#300) — The rear runs a 10.25" ring gear (Revolution F10.25-513L) in the 10.5 housing with the ARB RD140 carrier (Ford 10.25/10.5, 35 spline, all ratios). Confirm with ARB or Revolution that the RD140 flange and ring gear bolt pattern match the F10.25 gear in this housing before ordering, and confirm the pinion depth starting point (owner note: add roughly 0.120" to the pinion depth stack).
Ball joint delete clearance against ORA high steer arms (#299) — Verify the American Iron ball joint delete (upper and lower, welded) clears the Offroad Anonymous 05-16 Super Duty Dana 60 weld-on full hydro high steer arms through full steering travel (40 degree target with the 8" PSC ram) and full suspension travel.
Front axle ball joint delete bushing offset (0 / 1.5 / 3 degree) (#298) — American Iron ball joint delete bushing offset sets caster and camber together, summing to the bushing rating. Select after caster is measured with the Dana 60 under the vehicle at ride height. Every 15 degrees of bushing rotation gives 0.5 degrees of change on a 3-degree set.
4WD/4LO indicator — NP241OR position switch → PMU → HDX (measure switch at teardown) (#145) — Reversed 2026-09-18 — the 4WD indicator is wanted after all. (Previously closed as "omit the indicator.") Updated the same day for the transfer-case change from JK NV241 to TJ/LJ Rubicon NP241OR (#313), which makes this easier.
Turbolamik Aux: P/N (#48) — Confirm aux output channel + pinout configured for P/N (start interlock)
Turbolamik Aux: Reverse (#47) — Confirm aux output channel + pinout configured for Reverse signal -> PMU In 3

📋 Medium (9)

ABS sensor opening plugs, front and rear axles (#310) — With no ABS on the build, the tone rings are omitted and the wheel speed sensor openings must be plugged. An unplugged opening in the rear housing is a gear oil leak path.
Confirm ORA high steer kit quantity (per arm vs per pair) (#302) — Confirm whether the Offroad Anonymous 05-16 Super Duty Dana 60 weld-on full hydro high steer kit is sold per arm or per pair before ordering, so the purchase tracker quantity is right.
Steering Cooler Fan (electrical) (#101) — On PMU Out 8 (~15A, 180F inline thermostat); confirm actual Mishimoto fan draw fits budget
Steering Pump Specs (#99) — Kit pump PK40JP2-FH is Jeep 4.0L-only - source Cummins R2.8 PSC pump/bracket; flow/pressure/drive TBD
Rear Suspension Components (#98) — Coil rate, bypass valving, control arms, track bar, sway bar
Front Suspension Components (#97) — Coil rate, bypass valving, control arms, track bar, sway bar
Rear Driveshaft Specs (#94) — Custom (Tom Woods) decided - measure length at final ride height & order
Front Driveshaft Specs (#93) — Custom (Tom Woods) decided - measure length at final ride height & order
Transmission Pilot Bearing (#91) — If required by flywheel/crank combination

📝 Low (2)

Steering Reservoir & Fluid (#103) — Fluid = PSC/SWEPCO 715; remote reservoir (in pump kit) model/location + system fill qty TBD
Suspension Geometry (#102) — Departure and breakover angles (calculated from chosen suspension)

Build Tasks¶

Confirm the Back Bay Customs adapter fits the 1-1/8" Tandem Compact (vendor confirmed it against the 1.00" 260-15542)
Match the Z36 kit application to the donor axle years
Measure flex hose and park brake cable lengths at full droop
Cite OEM or vendor sources for the Z36 kit application, pushrod thread, and pedal ratio

Brake Booster - iBooster, master cylinder, adapter, harness, firewall plate, plumbing
Front Axle
Rear Axle
Suspension - Droop for hose and cable lengths

Owner build notes, 2026-09-16 — Z36 kit application, pushrod thread, park brake cable and hose lengths at full droop, 62/38 bias starting point. Not yet backed by an OEM or vendor citation; see Build Tasks. ↩↩↩↩
Owner decision, 2026-09-16 — Wilwood Tandem Compact 1-1/8" bore, sized for knockback margin with the Super Duty calipers. Supersedes the 1.00" 260-15542 selected 2026-05-30 for the TJ Rubicon calipers. Wilwood lists the 1-1/8" Tandem Compact as 260-15541 (noted on the Brake Booster page, checked 2026-05-30); confirm the part number and the Back Bay adapter fitment before ordering. ↩↩