S197 Mustang Coilovers - Coiled Over

Progressive spring rates are supplied by a pair of coil springs from Eibach's extensive ERS line, so spring rates are hugely adjustable. Shown is a typical S197 fitment: The red mainspring is 7 inches long, 2.5 inches in diameter, and a 350 in-lb unit. The black helper spring is 1.75-inch tall and yields 150 in-lb to soften the ride. It sits on the adjustable lower spring collar or perch. Rotating the collar raises or lowers the ride height.

Atop the strut is a steel-bearing retainer-the round disc. Eibach uses a Teflon-lined, spherical bearing in the plate and Nylock nuts on the studs. The pinched nuts Ford uses wear out the bearing retainer studs after several runs up and down the threads. Nylock nuts wear out their nylon inserts just as fast if not faster, but are far easier and cheaper to replace. The red button atop the shock shaft is the rebound adjuster.

A major hang up in making monotube shocks is how to attach fittings, such as the Mustang's sway-bar attachment bracket detailed here. Welding is verboten on monotubes due to tube distortion; that's why Eibach uses this thread-engaging pinch clamp arrangement. It has excellent purchase on the strut thanks to the thread engagement, yet it leaves the shock bore undistorted.

While not coilovers, the rear shocks are inverted designs like the fronts. Shown resting on its reservoir, the lower shock mount is a thing of beauty. It is machined from billet and anodized red. Note the beefy bushing.

At the rear, ride height changes are made using this adjustable spring perch. Holes in the collar give the adjusting tool a place to grab traction; in the background, the stack of main and helper spring show the in-car spring relationship.

As in the front, two springs are used at each corner. However, all meaningful spring rate is supplied by the red main spring; the shorter black spring is a secondary unit. Its sole job is to supply enough length and minimal pressure to keep the main spring from falling out of its pocket when the suspension is at full droop. Normally such extension occurs only when the car is jacked or hoisted.

Often dismissed as mere crash bumpers, the bump stops are often in play during hard driving. They supply a last bit of progressively stiff spring rate as the suspension approaches bottoming and are carefully designed to work in specific applications. The two supplied with the Multi-Pro kit fit the rear suspension.

This simple adjusting tool is supplied with the Multi-Pro kit. The ends carry different pins; They fit into holes in the adjusting collars so you can lever the collars around to vary the ride height.

Underhood, the Eibach test car used a strut-tower brace. It provided a handy place to mount the front shock reservoirs. Without a brace, the reservoirs can be mounted to one of the four bearing retainer studs poking through the strut tower.

Adjusting compression dampening is done with the large red knob atop the reservoir, while rebound is adjusted with this wire tool atop the strut.

At the rear, the reservoir is best attached to the framerail. You have to drill a hole for the self-tapping bracket bolt. Also, take care when tightening the bracket around the reservoir as excessive torque can distort the reservoir's bore, and thus the free travel of the piston inside it. Eibach's test car also wore the company's rear sway bar with its snazzy connecting-rod-like brackets.

Another look at the rear suspension shows the adjustable spring perch to advantage. The Multi-Pro kit ranges from 0.80 to 2.50 inches of lowering.