The Wilwood 120-13431-BK is a left-hand DynaPro 6A forged aluminum lug-mount caliper with six pistons on a differential bore: one 1.62-inch and two 1.38-inch stainless pistons. The manufacturer describes a reinforced triple-bridge body held together by five high-strength steel bridge bolts, and calls it the stiffest DP6 caliper it has built. Stainless pistons with high-temperature seals complete the hardware. For a track or hard-use car, that added rigidity helps keep pedal feel consistent under repeated heavy stops, which a stock single-piston caliper cannot match at this pad size.
The 7.3 square inch pad area and 2.4 cubic inch pad volume give this caliper considerably more friction material than a typical stock setup. The manufacturer confirms it is a direct interchange with other 5.25-inch lug-mount DynaPro and Dynalite calipers, so it suits an existing Wilwood lug-mount system without a full rebuild. The listed limits are a 13.00-inch maximum rotor diameter and a 0.38-inch rotor width. Searching for a DP6A left-hand 5.25 lug caliper with 0.38 rotor, the 6712 pad plate, or a 6-piston big brake upgrade will turn up matching hardware. Wilwood's assembly guidance for DynaPro installs calls for checking that the bracket seats squarely on the spindle mounting points and inspecting for casting flash or machining ridges before final torque, then using shims to center the rotor in the caliper.
The manufacturer lists 120-13431-BK as the left-hand mount. The right-hand counterpart is 120-13430-BK, so confirm the side before ordering.
The manufacturer states it offers direct interchange with 5.25-inch lug-mount DynaPro and Dynalite calipers. Confirm your rotor is 0.38 inches wide and no larger than 13.00 inches in diameter.
The manufacturer identifies the 6712 pad plate for this caliper and lists it as applicable to brake pads only. Verify pad compatibility and whether pads are supplied before ordering.
Wilwood's assembly instructions for DynaPro installs stress a squarely seated bracket, so check the spindle mounting points for interference before tightening. Shims between the bracket and spindle set the caliper alignment, and the rotor should sit centered in the caliper when viewed through the top opening. The manufacturer also specifies orienting the largest piston toward the rotor exit side of the caliper. Bracket, hat, and pad-plate requirements vary by application, so confirm them against your spindle and rotor before ordering.
