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Ford Bronco Suspension Rehash - 4-Wheel & Off-Road Magazine

Harry Wagner Contributor

Ford was the first of the Big Three to bring a radius arm, coil front suspension to market for a solid front axle, starting on the ’66 Ford Bronco. Ford continued with the F-150 and Bronco through the introduction of Twin Traction Beams (TTB) in the ’80 model year. This suspension configuration has a reputation for providing a smooth ride and admirable wheel travel, with a similar configuration still in use today on Super Dutys.

ford Bronco Suspension Rehash front Three Quarter Photo 49158417

The ’74 Early Bronco shown here is sporting a 5-inch suspension lift with quality front coils and rear leaf springs, but it still had some room for improvement. When we ran the Bronco up an RTI ramp it revealed that the short factory radius arms bind under articulation. Plus, the shocks stopped damping years ago. Our goal was to address these issues while retaining the quality components already in use.

Add articulation and improve the ride while retaining the quality components

Our first call was to Bronco specialist James Duff, who started making Bronco parts when the vehicle was introduced for 1966. Duff’s extended radius arms provide more articulation and yield a better ride and handling, particularly when paired with the long-travel Bilstein 5160 series shocks we added. The front shocks are mounted on Duff’s tubular shock mounts, which worked with our existing coil springs and accommodated dual shocks to control the nose-heavy Bronco.

ford Bronco Suspension Rehash flexing Suspension Photo 49158444

Our old suspension scored a 723 RTI score on a 20-degree ramp. The front radius arms were binding and the short shocks limited our travel. After our makeover the RTI score jumped to 1069, providing increased trail prowess and an improved ride to boot. After wrapping up the installation over the course of a weekend we hit the trail to test out the modifications. The ride on the road was greatly improved. The new shocks and the James Duff radius arms and supporting components provided greater stability and articulation than ever before.

We rebuilt the existing leaf springs with Slip Plate graphite paint and new bushings from Daystar before reassembling them and slinging them back under the Bronco. Bilstein 5160 remote-reservoir shocks were used in the rear as well, on a Cross Enterprises mount that doubles as a crossmember for added chassis strength.

The result doesn’t provide any more ground clearance or lift height, but it is light years ahead of the previous setup in terms of ride quality, articulation, and handling in the dirt and on the road. Mission accomplished.

PhotosView Slideshow James Duff radius arms are over 10 inches longer than stock, which minimizes the angle of the arm as the suspension cycles. This improves handling due to reduced caster change and eliminates binding. The arms are available in traditional Duff Blue or the silver vein powdercoat finish we chose.

James Duff radius arms are over 10 inches longer than stock, which minimizes the angle of the arm as the suspension cycles. This improves handling due to reduced caster change and eliminates binding. The arms are available in traditional Duff Blue or the silver vein powdercoat finish we chose.

The Duff arms are built from 2x1/4-wall tubing and use a 1-inch spherical rod end at the frame end instead of the quick-wearing pin and bushings that come from the factory. While this transmits more vibration into the chassis, the upside is far greater strength and articulation.

The longer radius arms put the driver-side frame mount right next to the swapped-in Atlas II transfer case in the Bronco. This required us to remove the transfer case and mount the hardware with the bolt heads on the inside of the frame.

James Duff doesn’t overlook anything. The company’s heavy-duty coil buckets are one piece and keep the coil spring from popping out during articulation. They come zinc coated for rust resistance too.

The factory shock mounts use a pin on the top of the shock, which, combined with the short length, really limits articulation. There is plenty of room inside the wheelwell for a shock mount that accommodates a longer-travel shock absorber.

The first step was to cut off the factory shock mount to make room for the new tubular James Duff hoops. The Duff hoops bolt onto the frame, but we welded them as well to ensure that they would not move.

One trick we have picked up over the years is to wax the bodies of our Bilstein aluminum shocks to keep them looking shiny even after they are subjected to road salt and grime.

Bilstein includes urethane isolators and worm gear clamps (foreground) with the company’s remote-reservoir shocks, while billet aluminum clamps (background) are an option. We ran hose clamps in the front due to space and the aluminum clamps on the rear shocks.

We used dual Bilstein 5160s in the front of our heavy Bronco and single 5160s in the rear. These are similar to the company’s 5100 Series shocks with a monotube design, a high-pressure nitrogen charge, and digressive valving. The 5160s add a remote reservoir for more fluid volume and heat resistance.

The rear suspension used quality leaf springs with several thin leaves, but the Teflon sliders were long gone, the bushings were shot, and the shocks were dented and leaking. We didn’t want to start from scratch, just improve on what was already there.

We retained the existing leaf springs but gave them a facelift. First we took off the rust scale with a wire wheel, then we etched them with KrudKutter before painting them with Slip Plate graphite paint.

Our bushings were in sorry shape, so we added new polyurethane components from Daystar to the shackles, leaf springs, and radius arms. Constructed from urethane instead of rubber, they are far more durable and can withstand the occasional oil or gas leak as well. Note that the James Duff radius arms have 4 degrees of caster built in, so we only needed a 2-degree C-bushing with the 5-inch lift on the Bronco.

The new rear shock mount from Cross Enterprises acts as an additional crossmember to strengthen the chassis and provides three mounting options. The Bilstein 5160 shocks place the floating piston in the reservoir instead of the shock body. This allows more travel out of a shorter shock body, which is perfect under the Bronco’s floor.

We placed the Cross shock mount as high as possible between the framerails and then welded it into place. Note that the fuel lines run along the frame in this location so you will want to disconnect them prior to welding.

Normally bumpstops are useful to keep the tires out of the sheetmetal. This wasn’t an issue with the trimmed fenders on the Bronco, but we still measured and properly positioned new Daystar polyurethane bumpstops front and rear to keep our Bilstein shocks from bottoming out.

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Ford Bronco Suspension Rehash - 4-Wheel & Off-Road Magazine

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