Tom Wilson
July 19, 2007
Photos By: Steve Turner, Courtesy of Steeda

Horse Sense: If you look closely in the background of our photos, you might see a photo of the No. 37 Steeda race car. Dario Orlando was kind enough to let us have some seat time with him in that Fox racer when it was new. We went 6,000 rpm in Fourth gear while it was fitted with 2.91 rear axle gears-do the math and get a shock. The occasion was an SCCA mini-enduro at Daytona and we used a stock seat. Yikes!

It makes no difference that the S197 Mustang is the best-handling, stiffest-chassied Mustang by a long shot, the aftermarket is always ready to make it better. As if to prove the point, we've previously shown Steeda's front suspension gadgets for the new Mustang. This time, we're presenting Steeda's matching rear suspension improvements for street-driven S197s.

Central to Steeda's S197 rear suspension mods is this combination of a billet-aluminum lower control arm and a U-shaped extended mounting bracket. The bracket lowers the rear of the arm to provide a more aggressive, harder biting, on-throttle traction hit.

These upgrades are a mix of chassis stiffeners and, more important, geometry changers. The geometry products are replacement control arms and brackets for the three-link suspension. Their purpose is to increase rear axle traction-the cat-on-carpet traction the drag boys call bite-when the throttle hits the floor. These pieces are likely most effective for the sharp throttle blasts featured in street driving or at the strip, although they'll certainly drive the rear axle into the pavement no matter where or when the power is applied.

As the newest Mustang has but a single link between the top of the differential and the chassis, Steeda's adjustable street upper control arm third link replacement is also a single piece. It's fabricated of stiffer materials and supported by stiffer bushings than the stock piece to reduce flexing under heavy load. Furthermore, it's adjustable for simplified pinion-angle adjustment.

Steeda notes that the third link is street friendly, even though it has stiffer-than-stock bushings. A sophisticated three-piece urethane bushing design is the reason. There is also a Competition Upgrade Kit for the third link if you have to have more. The upgrade kit substitutes an all-metal rod-end bearing for the urethane bushing. It transmits some clank and road hash into the driver compartment in trade for more precise axle location. It's best used on race cars and Saturday night shakers.

It's true that S197 Mustangs are stronger than earlier Ponycars, but when hitting with big power, extra bracing is a good idea. It's also likely to help in the long-term integrity of the chassis. Steeda's frame and torque-box braces are built from 4130 chrome-moly plated with yellow zinc. They're supplied with the necessary hardware (the chassis already has the required holes) and bolt between the inner and outer frame-rails. They should be welded into position for maximum benefit.

Steeda uses the more descriptive and traditional trailing arm designation for what Mustangers commonly refer to as rear lower control arms. Steeda's arms are whittled from billet aluminum and can be had with either streetable urethane ends or racy rod ends. Steeda says both styles are stiffer than the stamped-steel stockers, thus reducing wheelhop and aiding in precision.

Interestingly, Steeda offers the lower controls arms badged either as Steeda or Ford parts under the Ford's Official Licensed Product program. Steeda is also quick to point out that the company was the first to the market with an S197 rear trailing arm, a product of unusually close ties to Ford for an aftermarket tuning house.

There's another twist to the Steeda trailing arm story: they're required if you also want Steeda's lower trailing arm relocation bracket. This is a U-shaped stamping that lowers the control arms' rear-mounting point below its stock location under the rear axle. This changes the instant center of the rear suspension and gives the trailing arms on-throttle bite, the sort of grip more traditionally associated with ladder bars.

To disperse the extra loads the more aggressive trailing arms impose, Steeda offers the three-point framerail and torque-box brace. This is a welded 4130 tubing and plate. It ties the inner and outer framerails of the Mustang together and communicates at its third point with the trailing arm attachment point. Thus, it passes the loads from the control arms into the chassis without overloading the chassis pickup point.

Together, these parts fortify the S197 for hard acceleration action. To show you how they're installed, we followed along as Steeda fitted them to customer cars at the Pompano Beach campus. It's how the best get better.

Part Number Description MSRP
555-4405 Billet rear trailing arms $329.95
555-4105 Adjustable street upper control arm $179.95
555-8119 Trailing arm relocation bracket $129.95
555-5551 Three-point frame & torque box brace $239.95
555-6009 Rear brake upgrade, slotted or drilled $499.95

Those holes in the side of Steeda's trailing arm relocation brackets allow adjusting the height of the axle end of the trailing arm. The lower the attachment is the greater the bite. Built from mild steel, the brackets are zinc-plated for corrosion resistance and must be welded to the axle housing.

Shown mocked-up on an axle housing, Steeda's third link is strong to reduce flexing and adjustable for easily setting the pinion angle. Using a three-piece bushing at the axle end of the link and simple urethane bushings at the chassis end, Steeda says its standard third link doesn't increase noise, vibration, or harshness so you won't know it's in your daily driver Mustang, except for the handling improvement. The turnbuckle-style adjuster means the link can be lengthened or shortened without removing it from the vehicle. Just loosen the jam nut and turn the centersection. The link shown features the competition upgrade with its noisier but stronger rod-end bearing at the chassis end.

Ford's lower control arms are stamped steel, which is affordable and quick to make, but not the last word in strength. Steeda's replacement arms are billet aluminum for greater bending resistance, and they're a bit longer to work with Steeda's trailing arm relocation brackets. These arms are available with urethane (street) or rod-end (track) attachments. You also have a choice of Steeda or Ford logos.

Steeda got the installations started by gunning off the rear lower control arm attachment at the rear axle. The arm probably won't swing down until the front attachment point has been loosened. Notice how the car is supported on a twin-rail hoist with the car's weight resting on its tires. That's important when getting some of the brackets correctly installed, so don't do this job with the suspension hanging.

The front of the arm is undone by Steve Chichisola, Steeda's longtime wrench bender. Once this bolt is out, the arm will hang free but remain captured by the parking-brake cable.

Unclipping the parking-brake cable at the caliper end will allow it to be pulled through the stock control arms.

The stock arm and cable are unthreaded from each other. As some of the attachment hardware is reused in this job, you don't want to throw any bolts away until the job is complete.

The new Steeda arm can now be bolted to its front attachment, but don't bolt it to the axle yet. We need to install the relocation bracket first.

Like the rest of this job, hanging the control arm relocation bracket is a simple bolt-on affair.

Now the rear of the control arm can be installed to the relocation bracket and the whole thing cinched down. The typically tougher part is that the relocation bracket must be welded to the axle housing immediately. Steeda allows the car to be pushed from one side of the shop to the other to access the welder, but says under no circumstances may the car be driven before welding the top half-moon of the relocation bracket to the rear axle.

Finally, the emergency brake cable can be threaded through the Steeda control arm, reattached to the brake caliper, and clipped into place as shown here at its frontend.

To fit the framerail and torque-box brace, the two deflectors, or wipers, must be removed. Hang on to the bolts, as you'll reuse some of them.

Fitting the bracing into place can bring on a touch of the blacksmith. Depending on the build of the car, the brace may or may not need some light encouragement from a hammer. In any case, fit the braces and bolt them in. Sometimes, the bolt holes in the chassis may be not finished or bungered up. If that happens, omit that bolt.

What the frame brace really needs is some love from the smoke wrench. A few beads welding the brace and chassis provide the positive joining required to get the brace truly working and negate any worries about any missing bolts. The bolts are almost redundant given the welding.

While you have the car next to the welder, the relocation brackets can get their necessary smoke job. A spritz of paint over the welded area will slow the corrosion beast.

Unless you're doing the job, this is about all you'll see of the third-link installation. The third link is atop the differential and well-hidden from the camera. It attaches directly to a casting atop the differential and to a bracket between the third link and the chassis at the frontend. The basics are easy enough: remove the stock third link, assemble the Steeda link on the bench, then install it on the car. The tricky parts are remembering to lower the bracket at the chassis end before trying to remove the cross-bolt, and that there is a single bolt holding the front bracket from under the rear seat in the passenger compartment.

Prep the Steeda third link by bolting on its pinion snubber. This is simple wrench and bolt work.

Most of the work is at the chassis end of the link where several bushing sections and these thick metal washers are stacked together to form the bushing assembly. Shown here dry for clarity, these parts must be well lubed with sticky marine or synthetic wheel-bearing grease to avoid squeaks. Water washing away the lube is the long-term issue, so a waterproof grease is the way to go.

Here's the frontend of the third link installed. It shows how the pinion snubber faces down to impact the front of the differential when the suspension bottoms.

Sneaking the camera as close as it'll get, here's a peek at the finished third-link installation.

Steeda gives its 13-inch rear brake rotor a black oxide coating for corrosion resistance. It's also normally sold with slots, as shown, but can be had without slots and cross-drilled instead. There's no slotted and cross-drilled option.

While you're considering making your new Mustang go with Steeda's rear axle traction parts, you can also consider making it stop with Steeda's 13-inch Rear Brake Upgrade.

Designed to fit the S197 V-6, GT, and GT 500 Mustangs, Steeda's kit features larger diameter, wider, and vented rotors to reduce fade. Sticking with a 13-inch disc, Steeda avoids any issues with wheel fitment that 14-inch rear brakes can encounter, and the 13-inch size is powerful enough for any street-driven Mustang and probably all but the most outrageous race cars as well.

Another consideration is working with the stock ABS system. Get the rear brakes too large and the ABS has difficulty modulating the system and often malfunctions. Steeda avoided this issue by retaining the stock caliper with its brake upgrade. This preserves the stock brake fluid volume flow, which seems to be the major factor in confusing the ABS. With the larger diameter disc, however, the caliper must be mounted a little farther outboard, so the Steeda kit includes a beefy aluminum mounting plate to relocate the stock caliper. Don't worry-the stock caliper gives plenty of clamping force to work with the larger diameter brake disc.

Steeda also includes braided-steel brake-flex hoses with OE connectors for a bolt-in and bleed installation.

Count on approximately 2 1/2 hours to fit these rotors, as the rear axles must be removed from the axle housing to make the change. Slotted and cross-drilled discs are available; either kit is $499.95. Steeda says this rear kit is the perfect match for its front 14-inch system.