Wilwood's forged Dynapro 6A lug-mount caliper in red, left-hand configuration (part 120-13435-RD) is a six-piston caliper for 5.25-inch lug-mount brake setups. Wilwood offers direct interchange with all 5.25" pattern lug mount DynaPro and Dynalite calipers. That makes it a practical upgrade path for a builder already running that bracket family, since the new unit drops into the existing mounting geometry. The stainless pistons and high-temperature seals are the key durability points for heavy track or hard street use.
The buying case over a stock or cast caliper is clamping consistency under repeated heat cycles. The listing shows six stainless pistons, a 0.81 rotor width for this variant, a maximum rotor diameter of 13.00 inches, and a pad volume of 2.4. That rotor capacity covers larger performance discs that a stock-sized caliper cannot clamp. Owners on user forums commonly pair these calipers with the matching Wilwood bracket and pad combinations for drag, autocross, and road-course builds, so check your pad compound against your rotor width before ordering.
This is the left-hand red unit, 120-13435-RD. The manufacturer lists the right-hand red caliper under part number 120-13434-RD, so confirm the hand before ordering.
The manufacturer describes this caliper as a direct interchange for 5.25-inch lug-mount DynaPro and Dynalite calipers. Check your bracket against the 5.25-inch mount center, 0.39-inch mount hole, and 2.03-inch mount height before installing.
The manufacturer lists a maximum rotor diameter of 13.00 inches. For this variant, the listed rotor width is 0.81 inch.
The manufacturer sells a caliper mount bolt kit, 230-0204, for Dynalite and Dynapro calipers. It includes four 3/8-24 x 1.25-inch lock-wire drilled bolts, washers, and shims for alignment.
This is a bolt-on job for someone comfortable with brake work, but it needs careful alignment and bleeding. Wilwood's assembly sheets for Dynapro calipers say to mount the caliper so the largest piston sits at the rotor exit end, and they call for Wilwood Hi-Temp 570 fluid or higher. The manufacturer's technical guidance also says to bleed from the upward-facing screws, and to hold the caliper vertically if it is not bled in place. Owners on user forums advise placing a spacer between the pads during removal so they do not push out. Torque the mount bolts to the manufacturer's specification, use thread locker on the bolts as the assembly sheets direct, and keep brake fluid away from the pads and rotor.
