How Wilwood turns aluminum chunks into brake calipers

When it comes to upgrading your vehicle’s brakes, only a few names in the aftermarket-parts business come to mind. Wilwood is probably one of them. What goes into making the components of an aftermarket brake system? We wanted to find out, so we took a trip to Wilwood’s complex in Camarillo, California, which houses R&D, sales, marketing, manufacturing, and QC in a few very large buildings. In total, the location employs almost 400 workers. Two shifts keep Wilwood operating 16 hours a day, six days per week. We stopped by to see how the company builds brake systems, starting virtually from scratch.

To begin our tour, we met Mike Hamrick, events and promotions manager at Wilwood Disc Brakes. He told us that while Wilwood is known for its brake systems for performance cars and off-road trucks, almost half of its total business is in OEM (original equipment manufacturer) products, including heavy armored vehicles produced under military contracts. Wilwood’s research for one feeds the other.

Hamrick explained that while it’s not too difficult to improve the braking performance of a classic car or truck, increasing the track performance of a modern Mustang or Corvette is another matter. The factory brakes are often very well sorted and perform admirably. However, once a buyer adds a set of wider, stickier rubber to their car and pushes it on the track lap after lap, the factory rotors and calipers will eventually show their limitations.

Wilwood’s goal isn’t to just add braking power but to improve upon repeatability. “We’re trying to make [the vehicle] stop 10 feet shorter, 20 times,” Hamrick explained. Sometimes, especially with heavier vehicles, the way to get prolonged brake performance is to add mass to the rotors. That’s often the case with trucks to which a customer has added taller, heavier tires. Other times, braking can be improved while reducing weight. Reducing rotating mass and adding long-lasting braking is a huge win-win for track performance.

We asked Hamrick how Wilwood develops a brake kit for a specific car. It all starts in the R&D department. That is where vehicles get measured and engineers design the brackets and determine which calipers would be the best fit, or if a new caliper design is warranted.

This Stinger II measuring arm can pinpoint critical mounting locations to create a digital model. Engineers at Wilwood develop not only the brake components but also the fixtures for CNC machining. That helps streamline production, as fixtures can be designed for tooling to reach all areas that need to be machined, in as few operations as possible.

Company founder Bill Wood’s ’75 Ford and a Chevy C10 shop truck were in R&D when we stopped by. Wilwood bought the Chevy simply to get into that particular pickup truck market.

The R&D department includes all the equipment needed to machine a mounting bracket or caliper, including founder Bill Wood’s original Bridgeport mill that he used to make his first calipers back in the 1970s.

Not far from R&D, Wilwood operates two devices that put its parts to the test. This Chevy small-block-powered dyno runs on natural gas and puts all of its power into a heavy steel flywheel. A rotor and caliper mounted to the flywheel can be used to bed brakes for race teams looking to save time at the track.

Right next to that is another dyno. This one can simulate vehicle weight up to 30,000 pounds and even simulate laps at tracks to see how friction would change over the course of a race. Removing variables helps make A/B comparisons of pads and rotors much more useful.

Before a shipment of raw materials can start the process of becoming calipers, it gets inspected and vetted. That material, of course, includes caliper forgings, but even bar stock gets scrutinized on precision-ground tables, shown above, that serve as flat references.

About 90 percent of Wilwood’s calipers are made from 6061 aluminum forgings; the remainder are pretty evenly split between aluminum castings and billet aluminum. The forgings are sourced from across the United States as well as abroad.

A set of 14 CNC machines churn out the two halves that make up a caliper. Each machine uses a pair of four-sided “tombstone” fixtures that secure the raw forgings. Wilwood doesn’t want to share exactly how it makes its fixtures, but each one for this operation is about 12 inches square and 18 inches tall, and each holds several forgings on each of its vertical planes, held in place by pneumatic clamps. The machine mills each part on one tombstone while the operator loads the other.

Once the parts come off the CNC machine, they go into an abrasive tumbler for a few minutes to take off the sharp edges. In an eight-hour shift, each CNC operator will complete about 250 inboard and outboard caliper halves.

Three employees per shift tend the machines and keep them running cool and smooth. One task is to collect the aluminum chips from each machine and dump them into a hopper that turns the chips into compressed logs about three and a half inches in diameter. This step serves two purposes. First, it greatly reduces the volume of aluminum chips, helping make transport more efficient. It also squeezes out the coolant, which is recycled. When new shipments of raw aluminum are dropped off, those truckers pick up the scrap for recycling.

In addition to calipers, Wilwood also makes mounting brackets, rotor hats, and hubs. This single hub forging covers 130 different part numbers, depending on how it is machined. These complex parts used to require five separate machining operations. Now, two multi-tasking Mazak machines incorporate turning and milling to turn a hub forging into a finished part in just two operations. Each machine and operator can complete 250 hubs per shift.

To ensure top-notch quality, Wilwood moved all of its finishing and coating processes in-house. All Wilwood calipers get hard-anodized to give their surfaces a durable finish. This room is where it happens. Parts get washed to remove coolant from the machining process, then are dried off before going into an acid bath and getting charged with electricity to build a tough skin of aluminum oxide. The portion of the racks to which the parts get mounted are made of titanium.

After anodizing, race calipers are ready for assembly, but lots of aftermarket calipers get powder-coated. These women are responsible for carefully applying high-temp masking to the areas that won’t need coating.

Masked calipers are placed on racks, electrically charged, and sprayed with powder before heading into an oven to cure.

Once powder-coated, Wilwood can laser-etch or, in the case of this caliper, apply a logo using a screen-printing process.

Batches of completed parts are stored on pallets until it is time to begin assembly. Once a set of calipers is ready for assembly, workers pull all the necessary parts from the pallets, like the pistons, seals, and hardware.

Four lines of benches are filled with workers who assemble and test each part prior to packaging. These electric parking brakes are cycled to ensure they operate properly when voltage is applied. Completed calipers are then boxed and placed in the warehouse.

Wilwood sources its rotors from a number of manufacturers, and these components go through the same quality control process as the caliper materials. The worker at this station is applying E-coat, an electrically charged paint that will protect the rotor from corrosion.

Once an order is placed, staff vets it to make sure all of the right components have been selected. Workers then assemble each order from the inventory in the warehouse onto a cart and box it for shipping. Wilwood dropships orders for companies like Jegs, Summit, and Turn 14, from which the brakes will make their way to customers’ race cars, hot rods, and pre-runners.

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