Quadra Link Rear Suspension - Harnessing The Power

Walk through any national event, or even a local cruise night, and it's easy to observe that numerous car owners are under the impression they can simply bolt a bad-ass mill to the 'rails and instantly become king of the street or strip. The truth, however, proves that it takes more than brute horsepower to be successful at that game. In order to put the grunt to work, you need to be able to hook it up once it leaves the driveshaft. Handling and straight-line performance are more than just mere "buzz words" today; they are a major part of the performance gospel. When it came time to choose the path for Orange Krate, our second-generation project, there was no doubt that the car would need to handle like it was on rails while ripping through the gears, taking it to the dark side. To make sure all of its aggressive attitude could be harnessed, a call was placed to Detroit Speed for one of their cutting-edge new Quadra Link rear suspension packages.

A perfect way to upgrade from the factory leaf-spring setup, the Quadra Link system employs Detroit Speed's industry-leading four-link geometry combined with their new Swivel-Link technology, which creates a smooth, nonbinding performance suspension that's all business. Without the use of the standard Heim joints or urethane bushings, the new system utilizes tuned high-durometer rubber bushings that allow the suspension to fully articulate while retaining smooth and quiet operation. Combined with longer upper links to provide accurate pinion and U-joint angle control, an adjustable Panhard tube for rear axle lateral control during hard cornering, and Detroit Speed's aluminum-bodied adjustable coilover shocks, there's no doubt the car will be firmly planted to the earth. For this application, we also decided to upgrade the rearend with one of Detroit Speed's rock-solid, 9-inch Ford rear axle housings filled to the brim with all the right goods, including a nodular iron centersection and Moser axles. To be sure the car could stop on a dime, Baer Brake Systems got the nod for one of their Extreme-Plus braking packages featuring their massive 6S six-piston monoblock calipers and two-piece, cross-drilled and slotted 14-inch rotors. When dialing in the combination for the back half of your car, it's important to execute a plan to reflect what you ultimately wish to accomplish with it once it's completed.

If you plan on going fast, you’d better be ready to stop quickly! To be sure there is plenty of power for the job, the clear choice was Baer Brake Systems for their hard-core Baer Claw Extreme-Plus braking system, which includes a pair of their 6S six-piston monoblock calipers (manufactured from forged aluminum alloy) and their massive cross-drilled and slotted two-piece 14-inch brake rotors.

Prior to beginning assembly, it’s imperative to clean the inside of the axle housing. Peter Newell of Competition Specialties in Walpole, Massachusetts, got started by blowing any debris from the inside with compressed air. He then followed with a healthy dose of brake cleaner to remove any grease and dirt residue, then wiped the inside clean with a dry cloth.

To install the third member, Newell first mounted the provided gasket over the studs, sealing it into place with RTV on both sides. From there, he lowered the section into place and secured it using the supplied 3⁄8-inch nuts and AN washers. The nuts required a 35 lb-ft of torque setting.

Before the Moser 33-spline axles could be set into place, the axle seals were installed into the rearend housing. Note that the seals install with the flat side facing outward. Before installation, place a thin bead of RTV around the outside edge of the seal and be sure it is installed straight into the housing.

When installing the axles, note that the shorter axle is for the passenger side. First, slip the Banksia parking brake assembly and reinforcement brace over the axle bearing.Then, slide the axle into the housing. The assembly will bolt on in only one position.

Next, slide the axle into place, then slip the caliper bracket over the axle bearing and secure to the axle housing using the provided Allen bolts. Torque to 85 lb-ft for big bearings used here.

To secure the Banksia parking brake assembly into place, locate the access hole on the outer axle face, carefully thread the provided 3⁄4-inch long Allen bolts into place, and torque to 45 lb-ft to the axle retainer and caliper bracket.

Slide the brake rotor onto the axle end and follow by lowering the 6S six-piston monoblock caliper into place with the brake pads removed. Secure using the provided 12x35mm non-Vibra-Tite bolts to the intermediate bracket and tighten with a small wrench. Then install the correct caliper washers and retaining nuts and tighten.

Using a caliper, measure the gap from the rotor to the caliper body at four points—top outside and inside, bottom outside and inside—to determine if there will be any need to shim the caliper for the application to avoid the potential for excessive noise. Typically, getting these gaps close to 0.005 inch will keep noise to a minimum.

The completed rearend is packed with all the right stuff from Detroit Speed, Moser, and Baer to make sure this second-gen will remain nailed to the pavement.

Since Orange Krate was designed to take on plenty of performance driving, the original rear leaf-spring suspension had to go. We contacted Detroit Speed for their new Quadra Link rear suspension system, featuring their exclusive new four-link geometry designed for the best possible handling on the track and the street. Here you can see all of the immaculately designed components that will be fabricated to the rear portion of the car.

The Detroit Speed Quadra Link system incorporates their exclusive Swivel-Link technology, which allows for nonbinding suspension movement. Instead of Heim joints it utilizes tuned high-durometer rubber bushings for smoothness. Detroit Speed aluminum body coilover shocks and springs are the perfect complement to the package.

The kit comes with all the necessary templates to help guide you through the installation. Here you can see templates in place for the exterior leaf-spring pocket mount and inboard framerail. There is also one for the outboard framerail.

Once secured in place, team member Brian Jordan used a yellow marking crayon to outline the needed cuts to accommodate the new suspension upgrades.

Wearing proper eye protection, Jordan got started making incisions to the inboard frame-rail using an air-driven cutoff wheel. He then proceeded to the outboard framerail area using a Sawzall to remove the noted section of the rail. When completed, a new framerail closeout will be installed in this recess to allow for full movement of the Quadra Link.

For needed access to install the new exterior leaf-spring pocket mount under the car, Newell used the interior spring pocket mount template to mark the area to be removed and cut the section out with a Sawzall.

pBefore the template was removed, Newell center-punched the marked area for a new bolthole.

Once the new exterior spring pocket was test-fit into place, he followed with a 1⁄2-inch drill to open the hole and then added a provided J-clip. The unit was then temporarily secured into place with two original leaf-spring pocket bolts. Once final fitment was complete, the unit was welded into place using a Lincoln Electric Power MIG 216.

Here you can see the outboard framerail opening deburred and adjusted for the new filler panel, which was fitted with an air-driven grinder topped with a 50-grit disc. The filler panel was then clamped into position for final adjustments and then tack-welded.

Once perfect, it was MIG-welded into place.

With the new exterior spring pocket and outboard framerail filler panel in place, Newell finished welding the units.

To prepare for the installation of the exterior framerail doubler, the framerail must first get notched. Measuring forward from the front edge to the rear spring bushing on the inside of the framerail, mark a line at 235⁄8 inches on the bottom inside edge of the framerail. Use a straightedge to scribe the line on the bottom and both sides of the ’rail, then affix the framerail cutout template to prepare for the notch to be marked and cut.

Finally, a framerail closeout will be MIG-welded into place.

To locate the upper link pocket template use a straightedge positioned forward along the bottom of the framerail and scribe a line onto the seatback portion of the pan indicating the bottom of the rail. Then locate the center of the line and mark an outboard vertical line at the proper length depending on the framerail dimension. This will allow you to locate the upper link pocket template for cutting purposes.

Mark the spot and cut open with an air-driven cutoff wheel.

After test-fitting the framerail doubler assembly into place, it will be necessary to make a number of fine-tuning adjustments. These include trimming the upper pocket so it fits flush with the exterior floorpan doubler (which is designed as reinforcement to the upper link pocket). Once completed, remove the unit and secure it in a bench vise. With a 9⁄32-inch drill bit, drill 12 plug-weld holes into the assembly to prepare it for final installation.

Newell used a number of Vise-Grip clamps to secure the framerail doubler into place. With a level, he checked to be sure that the upper link pocket was vertically level and square to the vehicle.

The assembly was then MIG-welded into place and all welds were ground smooth.

The outboard framerail closeout panel was then MIG-welded into place with all welds being smoothed with a 50-grit grinding disc. Note that all of our grinding discs and cutoff wheels came from our pal Ray Williams at our local Sherwin-Williams Automotive Finish store in Medford, Massachusetts.

With all of the above steps completed for both the right and left side of the car, it was time to locate and install the transverse tube. Position the transverse tube so that it is horizontal from left to right and be sure it is exactly 3⁄8-inch away from the trunk pan. It is cut to fit properly to the track bar body mount. Trim the tube to fit against the left side framerail doubler (above the bend) and MIG-weld into place. Once installed, plug-weld the two transverse tube support brackets into place.

Inside the car, the internal floorpan doublers (which sit on top of the upper link pockets) were plug-welded into place to give plenty of additional strength to the area.

With all of the fabrication completed, the Swivel-Link adjustable upper and lower links were mocked into place to check for proper fit prior to the rearend installation.

With all of the fabrication completed, the Swivel-Link adjustable upper and lower links were mocked into place to check for proper fit prior to the rearend installation.

With all of the fabrication completed, the Swivel-Link adjustable upper and lower links were mocked into place to check for proper fit prior to the rearend installation.

The completed Quadra Link and rearend installed into the Orange Krate not only looks impressive, it will also make the car a force to be reckoned with once it hits the track. Talk about beefy. The sum of the parts makes a real bold statement for handling and braking performance.