The Wilwood Forged Superlite Internal caliper, part 120-11130-BK, is a four-piston aluminum caliper with 1.38" pistons for 1.25" rotors, finished in black powder coat. Wilwood presents the FSLI line as a swap-in for Superlite-style calipers that use 3.50-inch centered mounting tabs, which makes it a natural step up from a stock setup on a track or race build. Stainless steel pistons resist corrosion and slow heat transfer into the pads, and the square-faced, high-temperature o-ring seals are designed for controlled piston retraction and long life under sustained heat.
What justifies the price over a cheaper generic four-piston unit is the build: a forged aluminum body, stainless pistons, and a 3.00-square-inch total piston area. The manufacturer lists pads with 8.2 square inches of pad area and 4.9 cubic inches of pad volume, which gives more lining for repeated hard stops. The manufacturer also lists the caliper at 5.2 lbs, a useful figure when weighing unsprung mass in a build. Wilwood's two-piece bleed screws can be replaced individually, so a worn component does not force a full caliper swap.
Fitment depends on rotor and mount dimensions more than on a model list. The manufacturer rates this unit for rotors from 1.19" to 1.38" wide and 11.75" to 13.06" in diameter, uses a universal lug mount with 3.50-inch centers, and specifies the 7420 bridge-bolt pad. The caliper inlet fitting is a 1/8-27 NPT. Wilwood's assembly sheets for its Superlite kits call for red Loctite 271 on the mount bolts, shimming the caliper until the rotor is centered, and pointing the bleed screws up during install. Search terms this part matches include 120-11130-BK, FSLI four-piston 1.38 caliper, 1.25 rotor lug mount caliper, and Superlite 7420 pad.
The manufacturer lists a universal lug mount with 3.50-inch centers and positions the FSLI line as a replacement for Superlite-style calipers with 3.50-inch mounting tabs. A vehicle-by-vehicle application list was not confirmed in the manufacturer material reviewed, so check your bracket spacing and rotor dimensions (1.19" to 1.38" wide, 11.75" to 13.06" diameter) before ordering.
The manufacturer specifies the 7420 pad type, the same bridge-bolt pad used across Superlite six-piston calipers.
The manufacturer lists an O-ring kit (130-2658), replacement pistons (200-7516), a cross-over O-ring kit (130-10540), and a bridge bolt kit (230-7541).
Wilwood's kit instructions state that installation should be done by someone experienced with disc brake systems, and this caliper is best treated as a moderate-difficulty job. Plan on a torque wrench, red Loctite 271, and shims for alignment. The manufacturer's sheets advise coating mount bolts with Loctite 271 and torquing only after the caliper, pad, and rotor alignment has been checked. Shims of .035" are used to center the caliper over the rotor. Check that the pad's outer radius lines up with the rotor's outside diameter, and keep the wheel-to-caliper clearance at a minimum of .080". Safety wire on the rotor bolts is optional per the manufacturer. Reinstall the center bridge retainer snug without over-tightening it.
