Wilwood Forged Superlite 4R ST Front Brake Kit – Road Race | 1994–2004 Mustang SN95 / New Edge | 140-10692

This kit is configured for dedicated road racing on all 1994–2004 Mustangs, or any 1993 and earlier Fox Body that has been upgraded with the 1994–95 model SN95 spindles. Four-piston, nickel finish Quick-Silver FSL4R/ST calipers with Thermlock® pistons and internal knock-back damping springs are volume matched for system compatibility with either a factory vacuum power brake booster and master cylinder, or a manual balance bar style pedal with appropriately sized master cylinders. The kit includes two-piece 12.19" diameter Spec 37 alloy GT series directional vane rotors to comply with SCCA American Sedan rules, cross-overs into the NASA Pony Car categories, or any other sanctioned racing with 16" or 17" wheels. Unsprung and rotating weight are minimised by mounting the rotors to the OE hubs with forged aluminium hats. Each kit includes high-temp Wilwood race compound pads, machined billet radial mount caliper brackets, stainless steel braided flexlines, and all premium grade hardware. Ships fast across Canada and the US.

Sanctioning Body Compliance

The 140-10692 is specifically engineered around sanctioned road racing rules for the SN95/New Edge Mustang platform:

• SCCA American Sedan: The 12.19" Spec 37 rotor diameter and specification are sized to comply with SCCA American Sedan class rules, which govern maximum rotor diameter and brake system specifications for this class.
• NASA Pony Car: The kit meets NASA Pony Car class regulations and cross-class compatibility for sanctioned events.
• General sanctioned racing: Compatible with any sanctioning body that permits 16" or 17" wheels, as the 12.19" rotor requires a minimum 16" wheel for clearance.
• Verify with your series: Individual regional SCCA and NASA chapters may have specific rule interpretations. Confirm with your series registrar that the 140-10692 meets your class rules before purchase.

Forged Superlite 4R ST Calipers — Technical Detail

• Forged aluminium body: The Superlite caliper body is forged aluminium — stronger and lighter than cast equivalents at the same dimensions. Forging aligns the grain structure of the aluminium, producing a caliper that handles repeated race-level braking loads without fatigue.
• 4-piston radial mount: Four pistons (two per side) provide even pad pressure distribution across the full pad face — more consistent pad wear and braking force than a floating single-piston caliper. Radial mount configuration provides superior caliper rigidity vs lug mount designs, reducing caliper flex under maximum braking load and improving pedal feel consistency.
• Thermlock® phenolic pistons: Phenolic resin pistons replace the stainless steel pistons used in street-oriented calipers. Phenolic has significantly lower thermal conductivity than stainless steel — dramatically reducing heat transfer from the brake pad into the brake fluid. In road race use where sustained hard braking generates extreme caliper temperatures, Thermlock pistons are the primary defence against brake fluid boiling and the resulting loss of pedal pressure. This is the correct specification for any extended track or race use.
• Internal knock-back damping springs: Knock-back occurs when cornering loads cause the brake rotor to push the brake pads back into the caliper, requiring additional pedal travel to re-establish pad contact at the next braking zone. Wilwood’s internal damping springs resist piston knock-back, maintaining consistent pad-to-rotor clearance through corners and delivering consistent first-touch pedal feel throughout a race stint.
• Quick-Silver nickel finish: Nickel plating over the forged aluminium body resists heat discoloration and corrosion better than paint or bare aluminium — practical for calipers that see repeated high-heat cycles and road grime exposure in race conditions.

12.19" Spec 37 GT Series Two-Piece Rotors

• Two-piece construction: The rotor ring (iron disc) and hat (hub adapter) are separate components joined at assembly. The forged aluminium hat mounts to the factory SN95/New Edge hub — no hub replacement required. Two-piece construction reduces unsprung and rotating weight compared to one-piece rotors of equivalent diameter by replacing the iron hat section with lightweight aluminium.
• Directional GT series vanes: Internal directional cooling vanes create a centrifugal air pumping effect as the rotor spins — drawing ambient air through the vane passages from the hat to the outer edge, cooling the rotor from the inside during braking. Directional vaned rotors are left/right specific and must be installed on the correct side.
• 12.19" / Spec 37: The rotor diameter and specification are matched to the SCCA American Sedan rulebook minimum rotor specification for this class. The Spec 37 designation is Wilwood’s internal reference for the exact rotor geometry required by the rules. Running a larger rotor may not comply with class rules — this 12.19" spec is deliberately chosen for class compliance.

Master Cylinder Compatibility

Volume matching is one of the most frequently overlooked aspects of brake kit selection. The 140-10692 is volume matched for two distinct system configurations:

• Factory vacuum power booster and master cylinder: The kit can be used with the factory SN95/New Edge vacuum-assisted power brake setup without requiring a master cylinder upgrade. This makes the 140-10692 accessible for track day and club racing builds that retain street drivability — no pedal box conversion or manual master cylinder sizing required.
• Manual balance bar pedal: For full race cars running a manual pedal box (no vacuum booster), the kit is compatible with a balance bar style pedal assembly using appropriately sized master cylinders. Confirm correct master cylinder bore sizing with Wilwood or your brake system supplier for your specific pedal box configuration.

Fox Body Mustang Compatibility

The 140-10692 fits 1993 and earlier Fox Body Mustangs that have been converted to 1994–95 SN95 spindles. The Fox-to-SN95 spindle conversion is a common upgrade in Mustang road racing that improves suspension geometry, hub bearing durability, and brake component availability. If your Fox Body retains the factory Fox spindles, this kit does not fit — it is specific to the SN95 spindle geometry.

Kit Contents

• Wilwood Quick-Silver FSL4R/ST 4-piston calipers — nickel finish, Thermlock pistons, knock-back springs (pair)
• 12.19" Spec 37 GT series directional vane rotors with forged aluminium hats (pair, left/right specific)
• Wilwood high-temp race compound brake pads
• Machined billet radial mount caliper brackets (pair)
• Stainless steel braided brake flexlines
• All premium grade hardware

Front kit only — rear sold separately. 1994–2004 Mustang SN95 / New Edge all models. Fox Body with 1994–95 SN95 spindle conversion. SCCA American Sedan and NASA Pony Car compliant. Requires 16" minimum wheel. Thermlock phenolic pistons. 12.19" Spec 37 directional vane two-piece rotors. Volume matched for factory booster/MC or manual balance bar. 52 lbs.

Specifications

• Brand: Wilwood Engineering
• Part Number: 140-10692
• Kit type: Front big brake kit — road race
• Caliper: Forged Superlite FSL4R/ST — 4-piston radial mount
• Caliper finish: Quick-Silver nickel
• Piston type: Thermlock® phenolic
• Rotor diameter: 12.19"
• Rotor type: Spec 37 GT series directional vane, two-piece
• Rotor hat: Forged aluminium — mounts to OE SN95 hub
• Minimum wheel size: 16"
• Application: 1994–2004 Ford Mustang (SN95 / New Edge) — GT, Cobra, V6
• Fox Body: Compatible with 1979–1993 with 1994–95 SN95 spindle conversion
• Master cylinder: Volume matched for factory booster/MC or manual balance bar
• Includes: Calipers, rotors with hats, race pads, brackets, flexlines, hardware
• Rear kit: Not included — sold separately
• Kit weight: 52 lbs