The Wilwood 120-9705 is a DynaPro Lug Mount caliper made from forged billet aluminum with a black powder-coat finish. It has four 1.38-inch stainless pistons and a 5.25-inch mount center. Wilwood presents the DP line as the newer generation of calipers for applications that previously used its long-standing Dynalite series, so it is a direct upgrade path for those setups.
Compared with a stock single-piston caliper or a cheaper cast four-piston unit, the case for this caliper rests on its construction and clamping area. The total piston area is 3.00 square inches, which spreads clamp force across the pad face. The forged body is the durability argument for repeated hard stops on track or at the drag strip. The manufacturer does not publish a heat or fade rating for this model, so confirm duty expectations before committing to a track-only build. For fitment, the manufacturer lists a universal mount side and a maximum rotor diameter of 13.06 inches with a 0.38-inch rotor width. Search terms this part matches include 5.25 inch lug mount four piston caliper, 1.38 piston 0.38 rotor caliper, Dynalite replacement caliper, and forged billet track brake caliper.
The manufacturer states that OEM rubber brake hoses generally cannot be adapted to Wilwood calipers. The manufacturer's install guidance prefers steel adapter fittings at the caliper and enough steel braided line to allow for full suspension travel.
No. The manufacturer's specifications list no dust boot for this model, so keep the exposed pistons clean and protected during wheel and pad service.
Per the manufacturer's DynaPro install sheets, shims are added or removed between the caliper and the mount bracket until the rotor sits centered in the caliper.
The manufacturer's install sheets state that installation should be performed only by people experienced with disc brake systems. Plan on a torque wrench, lightweight oil for the caliper mounting studs and nuts, and red threadlocker for the mount bracket bolts. Check for interference from the "ears" some spindles have where OEM calipers mounted, and remove only as much material as needed. Set the rotor centering and pad height with shims before final torquing, and bleed each caliper, ending with the one closest to the master cylinder. Owners on user forums who have rebuilt DynaPro calipers recommend a clean, well-lubricated reassembly, so inspect the seals and bleeder hardware when you have the caliper apart.
