The Wilwood 120-10937-RD is a red powder-coated D52 dual-piston floating caliper, built as a direct bolt-on replacement for the factory single-piston D52 caliper on many 1968-96 GM passenger vehicles and trucks. It uses a forged billet aluminum body, stainless steel pistons, and competition-style high-temperature seals, which Wilwood says address the rust, bore pitting, and seal failures common to OE designs. Two 2.00-inch pistons give 6.28 square inches of total piston area, and the caliper weighs about 5.5 lbs. That makes it a practical upgrade for a street-track 1968-96 GM build that needs more clamping force and better heat tolerance than a worn stock unit, without moving to a larger master cylinder.
This caliper is designed for 1.04-inch rotor width and mounts over stock rotors in the factory location, using original-style D52 pads and the OE 7/16-20 banjo inlet. Before you tear down the old setup, check the brake lines: per the manufacturer's kit instructions, pre-1978 lines with a 7/16-20 banjo bolt adapt to D52 calipers, while 1978-and-newer lines with a 10 mm x 1.5 banjo bolt need replacing. Search terms buyers commonly use for this part include D52 dual piston caliper 1968-96 GM, 1.04 rotor caliper upgrade, 7/16-20 banjo D52 caliper, and red D52 big brake caliper.
The manufacturer lists this 120-10937 caliper for 1.04-inch rotor width. Its 1.28-inch-rotor D52 caliper is a separate part number, 120-10938, so confirm your rotor width before ordering.
Per the manufacturer's D52 kit instructions, pre-1978 OEM lines with a 7/16-20 banjo bolt adapt to these calipers. Lines from 1978 and newer with a 10 mm x 1.5 banjo bolt require replacement.
Wilwood's D52 assembly instructions say installation should be handled by people experienced with disc brake systems, so this is best suited to a home mechanic who has done brake work before. Clean and degrease the mounting brackets, and make sure they are square and parallel to the rotor face, because bent brackets can cause pistons to stick and pads to wear unevenly. Coat the slide pins and sleeves with white lithium grease, but keep it off the threads. Mount the caliper, confirm the wheel turns freely with no interference, and route the hoses clear of suspension and steering components. Pads, sleeves, and fittings are not part of the caliper itself, so confirm what you need for your application before starting. Wilwood's full kits include them. Get the torque values for your specific bracket and kit from the manufacturer's instructions.
