The front suspension of our vehicle was in pretty good shape. If we were building a mild daily driver, we could have simply refurbished it with some new bushings and ball joints, for example. A show car would have received more attention, primarily from a cosmetic perspective with mostly the same parts being used. Since we are more concerned with function in our weekend cruiser, we used some modified components that are not required for a daily driver or desired for a true show car. The parts we chose are all relatively inconspicuous, as front suspension components tend to be, and generally resemble the factory parts. I show an overview of the installation for these parts and also describe the rationale for using them. Your decision to use these or similar modifications depends on your intended use of the vehicle, your priorities, and your budget.
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For lower control arms, there are many options. Those building a daily driver or a show car generally just go with stock replacement parts, albeit most likely with different levels of quality and/or preparation. Those building a more performance-oriented vehicle with minimal concern over retaining the factory look probably go with aftermarket tubular arms if the budget permits it.
We took a mid-road approach, which provides most of the benefits that switching to a tubular arm provides, yet does not sacrifice the stock appearance. As you see in the following photos, the change in appearance is relatively subtle, even though the improvement in performance is quite considerable, and noticeable. Installation is also not much different than stock.
The upper control arms are the parts most likely to simply be rebuilt, though they can still be enhanced somewhat. As long as the main stampings are in good shape (no major rust, corrosion, or cracks), they can be reused after some cleaning. A run through the media blaster and some good paint should be all that’s needed to prepare them for reassembly. The choice of components used during reassembly can be optimized a bit, as I show in the photos. Aftermarket tubular upper arms are also available for those who use their higher-performance and/or racing vehicles more aggressively.
Upper Control Arm Rebuild Step by Step
MUSTANG RESTORATION: UPPER CONTROL ARM REBUILD- STEP #1
Rebuilding the upper control arms is not especially difficult, but it does involve some special procedures, which we will cover in the next few photos. All of the parts needed for a typical rebuild are shown here. Note that the control arms we used accept fourbolt ball joints (left). This design is a better choice than the threehole design on the right because it is stronger and uses a more easily found ball joint. There’s no real functional difference other than the greater load handling capacity. The shaft and nut assemblies can be reused if they are not worn or otherwise damaged. New ball joints should always be used along with new grease seals/boots and zerk fittings. We’ll upgrade the spring perches, shocks, and springs, but first we need to make sure the platform they work from is both properly assembled and adjusted. There’s not quite as much potential for improvement with the upper control arms as there is with the lowers, but attention to detail can still pay significant benefits.
When rebuilding upper control arms, make sure the threads on the arm itself and the retention nuts are in good shape. It’s common for these to strip or wear to the point that new parts are required. These parts should be as clean and free of any surface irregularities as possible before you assemble them. If the nuts still don’t turn freely in the arm, use some anti-seize compound or grease to make sure they do. The nuts will be fully tightened down to about 120 ft-lbs or so (check the factory manual) on the arms so you don’t have to worry about the lubricant making them prone to loosening. Similarly, the grease that goes on the ends of the support shaft lubes the insides of the nuts, so you can be sure that some grease migrates to there anyway. Liberally grease the threads of the shaft and the ID of the seal prior to installing the rubber seals on the shaft. Also grease the interior of the retention nuts. Use relatively tacky grease that does not run out if it gets hot or wet. Be generous since both the type and amount of grease used will play a big role in reducing wear of the shaft/nut threads over time. The grease also helps make the control arm rotate more freely once everything is assembled, so also coat the face of the seal where it contacts the control arm. This will not only reduce “stiction” and improve the ride quality somewhat, but it will help reduce seal wear as well. There’s no need to pack the inside of the nuts with grease. Just make sure there’s enough to coat the threads fully and have a little left over for insurance.
MUSTANG RESTORATION: UPPER CONTROL ARM REBUILD- STEP #2
After all of the parts are assembled, it’s crucial that you center the shaft in the control arm. Do this by measuring the distance from the inner surface of the control arm to the center of the mounting bolt hole on each side. You can also use one of the edges of each hole. Be consistent and make sure the point you use is the same distance from the control arm on each side. If there is a difference, just rotate the shaft in the correct direction to balance it out. Don’t worry about how the seals look or if the letters on the shaft are showing. The critical requirement is that each hole is the same distance away from the inside of the arm so that the arm is centered.
MUSTANG RESTORATION: UPPER CONTROL ARM REBUILD- STEP #3
Before installing the upper control arms on the vehicle, it is a very good idea to just rock the shafts back and forth to loosen them up a bit. This also helps properly seat the seals and make sure the grease is properly distributed. Do not rotate the shafts too far. If you do, they are no longer properly centered. Just rocking them back and forth through about a 120-degree arc should do it. You will likely need a fairly long (and strong) tool to get enough leverage to move the shafts, at least at first. Be sure to avoid damaging the shafts or their mounting holes. Any scratches, scrapes, or gouges could increase the chance of breakage under heavy loads. When the shafts can turn somewhat freely, still with some drag, you’re done.
MUSTANG RESTORATION: UPPER CONTROL ARM REBUILD- STEP #4
The mounting bolts should be pressed into the control arm shafts rather than trying to pull them in by tightening the nuts. Pressing them in with a hydraulic press or similar equipment ensures the bolts are fully seated; the serrations shown are completely engaging the shafts. It also helps avoid damage to the inner fender apron and/or to the bolt threads. With the bolts fully pressed into the arms, inspect and clean the threads with brake cleaner (or similar) if needed.
They generally won’t be cost effective for a simple daily driver and clearly won’t have the authentic look wanted for a show car. As with the lower arms, we were able to improve performance over stock with minimal difficulty, expense, or change in appearance.
Different vehicle applications have slightly different hardware combinations, but the procedures and components shown should work with all but the most unique combinations. In many cases, parts can be interchanged and care should be taken in deciding which to use. I point out a few of these issues as we proceed.
Rebuilding the control arms is the major task when restoring and/or enhancing the front suspension of your early Mustang. The remaining work mostly involves choosing the appropriate components to install for your application. As you see in the photos, we went with high quality components that offer a significant performance advantage yet look similar to stock components. Some of these may not really be necessary in a daily driver or correct for a show car. We chose them to be consistent with our desire to make meaningful improvements where possible, consistent with our intended use of the car as a weekend cruiser.
For high-performance levels and/or those building racers, there are additional options like coil-over shocks and tubular anti-sway bars, for example. These can undoubtedly provide additional benefits in a more aggressive driving situation, but they cost more and diminish the factory looking appearance.
Written by Frank Bohanan and Republished with Permission of CarTech Inc