Tom Wilson
August 18, 2004

Step By Step

View Photo Gallery
138_0408_01z Ford_mustang_hatchback Left_front_view
Sitting 1 inch lower than stock, our rejuvenated suspension gives thelooks and handling improvements craved by street drivers.
138_0408_02z Ford_mustang_hatchback Right_front_view
(above & below) Besides the clues given by tire wear and through thesteering wheel--wandering or imprecision--you can spot worn steering andsuspension parts with a few easy checks. Feeling for play at 12 and 6o'clock in the tire will uncover loose wheel bearings (an adjustmentissue) and worn ball joints. Any play in the tire from the 9 and 3o'clock position signals worn tie-rod ends. You can spot the bad areavisually while a helper wiggles the tire. Look for where the motionstops in the steering or suspension and that's your troublemaker.Likewise, wiggling the steering wheel and observing the rag joint andtie rods will give a quick indication of their condition.
Admittedly there isn't too much to see when eyeballing control-armbushings such as this rear upper arm at the differential. However, agood, up-close examination with a flashlight should uncover deeplycracked or partially squished-out bushings. Be careful, most of thevisible bushing area is usually a metal backing. The rubber part isnormally visible only at the outer ends. This one looks OK.
Urethane bushings are readily available and provide a great increase incontrol-arm precision, but they require careful (and sometimesphysically difficult) installation bordering on suspension blueprinting.If you're setting up a dedicated open-track machine, then such bushingsare worth the effort. But daily drivers don't benefit from this extrawork because they aren't driven hard enough to greatly deflect the stockbushings. These are front lower control-arm bushings from MaximumMotorsports at $59.95.
The rear upper control-arm bushings seem dedicated to remaining in thedifferential's iron ears. This $39.95 bushing press from MaximumMotorsports makes persuading the bushings in and out much easier.

While never known as the tightest ships in the fleet, Fox-chassis Mustangs are at that age where creaks and groans accompany nearly any motion. Good as you are to your 5.0, no doubt you've noticed it wandering on the freeway, wallowing through culverts, and generally feeling loose. It's time to lavish some love on the chassis.

From the most fastidiously maintained personal favorite to run-hard beaters, old 5.0s fall prey to time and mileage. With 100,000 miles being low mileage for today's Fox Mustangs, is it any wonder the typical chassis wear points are highly suspect? Tires, struts, and shocks are all no-brainer maintenance items in this age group. But for many owners, changing bushings in the control arms, steering rack, sway bars, and other areas is a first-time concern, as is the condition of the rag joint in the steering, the inner and outer tie rods, the pinion snubber, and the spring isolators. In short, if it's rubber or plastic and it's been working for a decade or more under your Mustang, it should at least be looked at.

To get a better idea, slide onto your imaginary creeper with us and take a quick tour from grille to taillights under a 5.0. Item one is the front sway bar. A simple steel bar, nothing bothers this thing short of hitting a tree, but the bushings it pivots in soften, crack, and loosen up, and the end-links almost always bend. The bending comes from the sharp angle the end links are contoured to during maximum sway bar deflection. Curiously, the light blue end-link bushings are probably the most durable bushings in a 5.0. While likely slightly deformed, they are probably OK.

Next back is the steering rack. Its only common wear items are the inner tie-rod ends. These are a typical cause of freeway wander and "loose" steering. The rubber boots on the rack are occasionally rotten or punctured as well.

On the outer end of the rack are the outer tie-rod ends. These do wear, but not as rapidly as the inner variety. Also, they are easier and less expensive to replace, so they may have already been changed.

Between the steering rack and the upper steering column is an interme-diate steering shaft, commonly called the rag joint or steering isolator. It is a common wear point and source of wandering steering on 5.0s. Cracking and deformation are the typical failure modes. Any visible play while a buddy works the steering wheel back and forth in small, sharp motions is also cause for replacement.

On the front lower control arms, consider the control arm itself--they do crack. In addition, the ball joint at the spindle end will wear and the large inner bushings where the arm attaches to the K-member crack and mush with age. A steady diet of extremely hard driving will even squish the control arm bushings out of the A-arms, a condition the mechanics at the Bondurant driving school reported took about one month to occur on the school cars. Those cars are driven like rented mules all day, every day, and we mention the phenomena in case you're working on an old race car or your 5.0 has taken a couple of kids through high school.

The front struts are obvious wear items, so we won't detail them here. Their companions, the springs, are durable and essentially never go bad, but not so the rubber isolators at both top and bottom of the springs. Look for deformation and cracking.

The weakest point of the Fox chassis is the midsection, in a line running athwart the car just forward of the rear of the door opening. Look for cracks in the floorpan, especially around the holes where the seats bolt to the floorpan. The solution, as well as the preventative medicine, is a beefy set of weld-in subframe connectors.

Horse Sense: Should you be opting for more aggressive lowering than we are in this story, you might consider upgrading to adjustable tie-rod ends, commonly known as bumpsteer kits. Bumpsteer is a symptom of toe changes from the suspension moving up and down, which can actually cause the car to change direction. Maximum Motorsports offers two variations of the adjustable tie rods, one with a tapered stud for stock K-members and one with a bolt-through spindle for its tubular unit. Obviously the latter offers a greater range of adjustment than the former. It also costs a bit more at $149, versus $139 for the tapered-stud version.

Step By Step

View Photo Gallery
The above photo shows what the typical 100,000-mile front sway-barend-link looks like--bent. Easier to see once dismounted, this bend canbe detected with the link in place. Also normal is the fair condition ofthe factory bushings; they're tough. If you are retaining the stock swaybar, then the $19.95 Prothane end-links from Maximum Motorsports (below) are aneasy fix. Urethane bushings for the sway-bar chassis mounts are alsoavailable.
Tired steering isolators are best handled with all-metal, needle-bearingsteering shafts. These may, but typically don't, introduce somepower-steering pump noise into the steering column, but the increase inprecision is definite. Maximum Motorsports is the source for this$159.95 unit.
Your Ford dealer is the source for inner tie-rod ends. The trick withthese is grasping the steering rack and dealing with the high torque,unusual shape, and size of the "hex" on the tie-rod ends. We paid $38.02apiece at our dealer for these, while the local alignment shop quotedabout $250 for parts and labor to replace both inner tie rods.
At $209.87 our rebuilt steering rack from seemed areasonable alternative to changing our inner tie-rod carries a good selection of "hard parts" such as brakerotors, steering parts, and so on at reduced prices thanks to a moredirect path between manufacturers and consumers.
(above & below) Spring isolators soak up irritating noises and are vital in a streetcar. In the left photo are Maximum Motorsports urethane replacementisolators. The two-piece front isolators are $26.95 and are thicker thanstock. These gave our car an extra 1/2 inch of ride height by raisingthe spring slightly in the lower control arm's pocket. This was finewith us, as we didn't want the full 1.5-inch front lowering from theEibach springs and were pleased with the resulting 1-inch drop.Maximum's rear isolators are $18.95, give a stock ride height, and are ahuge improvement over the too-hard stock isolators--which you can see endup totally destroyed.

Likewise, with the rear suspension, eyeball the chassis where the upper and lower control arms attach. In cars driven hard --drag racing starts are the culprit--these attachment points can be cracked or torn away from the chassis proper. Reinforcement with patch panels and a welder are the answer.

More commonly, the control-arm bushings may have succumbed to ozone cracking and hard driving. This is most important with the lower control arms; the upper arms are built with soft bushings to provide the definitely needed compliance in the rear suspension to avoid binding between the upper and lower control arms. When eyeballing the lower control-arm bushings, keep in mind the forward end of the lower arm uses an elongated bushing, so don't be overly alarmed if you can see some clearance between one side of the bolt and rubber bushing.

The spring isolators between the coil spring and the lower control arms are almost certainly turned to powder. This is almost always the cause of the "settling" of the rear ride height normally attributed to the rear springs. While the springs can settle with age, it is not nearly as often as is commonly thought. It's usually just dusted spring isolators.

Of course, the hard-working shocks are almost always ready for replacement. Another given is the rear sway bar is just fine. It bolts directly to the lower control arms and uses no rubber bushings, so it's good for life. Also, the kicker shocks are probably OK as is. They're there to dampen rear-axle reaction motions and thus avoid axle hop during hard starts. If axle tramp is not an issue with you, there's little need to service these units.

What to Do About It
The fun begins when formulating a plan of chassis restoration. A couple practical issues soon become apparent. For starters, a few of the common wear items are obsolete from Ford, so you'll have to go aftermarket for some parts. You'll want to go aftermarket on other parts because a handful of the stock Ford parts are best replaced with stronger aftermarket items. And, most importantly to the enthusiast, simply renewing factory levels of performance is often not as exciting as stepping up the game somewhat. Therefore, fixing up a Fox chassis is just the excuse you were looking for to install a set of lowering springs or more sports-oriented handling. Other times--and you old-timers reading this magazine know who you are--providing a showroom-new ride to your Fox is all you want. Let the kids pound their kidneys.

To get to the bottom line, restoring a Fox chassis typically means upgrading a Fox chassis, and for that, a parts package often makes sense. There are several choices readily available, depending on your car's condition, desired result, and budget. Should you want them, total performance suspension replacement and chassis mods are available for north of $5,000--but that's not what we're addressing in this article.

This time around we're aimed at daily driver Mustangs--our own 150,000-mile '91 5.0 LX hatchback proved a good example. Never raced, and used as a daily driver by two older enthusiasts its entire life, it was still a candidate for suspension work. We admit it was generally "loose," but what got us to finally look underneath was a lazy wander on the freeway. That turned out to be a worn inner tie rod. Simply replacing it would have returned the old hatch to daily service but still not quite showroom-new manners, and certainly nothing as precise as would be desirable.

For a casual driver such as our car, a favorite package is the Eibach Pro System Plus--offered direct from Eibach and numerous dealers, including Maximum Motorsports, for example. This is an affordable ($1,247.35) spring, shock, and sway-bar kit offering a 1.5-inch lowering with a ride quality a notch more sporting than stock. Fitting it would give us fresh shocks all around, as well as the new ride height from the new springs and the matching roll stiffness from the slightly larger sway bars.

Other parts were sourced mainly from our local Ford dealer and Maximum Motorsports. The photos and captions have details on these, but the idea was to replace the necessary items and support the Pro System Plus kit with durable isolators and other small parts.

While not shown here, the Ford Racing Performance Parts catalog offers front and rear upper control arms, complete with bushings and ball joints. These are excellent options should you have worn control-arm bushings or cracked control arms. The price is reasonable ($189.95, front; $102.90, rear) installa-tion is as simple as it can get because the bushings and ball joints are already mounted in the control arms, and upgraded ball joints and bushings are fitted where appropriate. FRPP also offers heavily upgraded rear lower arms as well.

Step By Step

View Photo Gallery
What's great about Eibach's Pro System is it is a well-engineered springand shock kit designed for enthusiasts. Paired with stock isolators, itgives a 1.5-inch lowering with a nose-low rake. The gas shocks arevalved to Eibach's specification to work precisely with their springsand give great control. Add Eibach's sway bars to the package and youhave the Pro System Plus at $1,247.35 for everything.
Slightly larger in diameter than stock, the Eibach sway bars give aworkable increase in roll control for a flatter, more corner-friendlyattitude. The front bar is hollow to save weight, and installation iseasy.
Eibach engineers put considerable effort into their bumpstops, which fitover the shock shafts. More than simple cushions to avoid suspensiondamage, these bumpstops actually add a bit of spring rate during hardmaneuvers and provide a more predictable, driver-friendly personality asthe suspension reaches its limits. That said, the Pro System Plus issharper edged at the limit than the stock arrangement, which startsplowing the front end and gradually makes things worse should you tryharder. The Eibach suspension works well driving up to about a 7 on ascale of 1-10, then the rearend gives up with more authority than stock.This makes the Eibach system much more fun to drive on the street andfaster at the track, which is the only place you'll get to 7/10 driving.

Our Experience
On our '91 hatch, we had Eibach install its Pro System Plus kit, a new power-steering rack, Prothane urethane steering rack bushings (supplied by Maximum Motorsports), and Maximum Motorsports urethane spring isolators front and rear. We reused the existing outer tie-rod ends along with the original rag joint in the steering. (We'd go with a solid shaft or new rag joint along with FRPP front control arms if we were to redo this job, to ensure maximum longevity from this hopefully do-it-once maintenance and upgrade).

The steering rack was an interesting twist on dealing with inner tie-rod ends. A rebuilt Ford unit sold by, the rebuilt rack retails for $209.87, and is possibly easier to change than the inner tie-rod ends (they're heavily torqued and require large wrenches). If there is a downside of changing the rack, it's the sometimes oily mess from opening and flushing the power-steering lines. But depending on local labor rates, this option may beat having the tire and alignment shop install only inner tie-rod ends.

When finished, our Mustang stood a perfectly beautiful 1 inch lower than stock, rather than the usual 1.5-inch drop advertised for the Pro System kits. This is because the large, urethane Maximum Motorsports spring isolators are thicker than stock and so provide a small ride-height lift. Stock isolators and the Eibach gear would drop the ride height 1.5 inches. Lowering fiends have been known to leave out the isolators--not recommended due to noise and deteriorating handling--and get a 1.75-2.00-inch lowering. That's too much lowering for optimum handling, but some folks will do anything for looks.

The ride is slightly stiffer than stock, daily-driver friendly, yet firmly controlled. The steering is a notch tighter than stock, and generally the car is more eager and willing to hustle through turns. So far we've noticed only minor increases in front-end scraping out of the steepest driveways, or dragging our lower-than-stock exhaust over speed bumps and such.

It's been the fun way to take care of old chassis issues!

Photo Gallery

View Photo Gallery