Mark Houlahan
Tech Editor, Mustang Monthly
January 24, 2014

Vintage Mustang suspension upgrades abound. You can flip through this very magazine and find all manner of suspension upgrades from stock replacement to trick weld-in systems. While welding in multi-arm/multi-link suspensions or grafting in suspension designs from other vehicles (or from newer Mustangs) often leads to a car with great track-like handling, sometimes you just want better handling that only requires basic hand tools and keeps the stock suspension configuration. Let's face it, coilover struts, four-bar rear ends, and the like aren't for everyone and for the typical weekend cruiser who just wants to be able to take a highway on-ramp at speed and feel some g-forces once in a while it is most likely overkill and a waste of budget dollars.

Keeping with the "bolt-on" theme means you can upgrade your first gen Mustang's suspension yourself in your home garage using hand tools, some jack stands, and a free weekend. At worst you'll have to fab up, buy, rent, or borrow a coil spring compressor, but otherwise the work is a typical nut and bolt affair. Using a stock-type suspension system also means there's no fabrication or drastic changes to your Mustang's chassis that are required, keeping the stock look of the car but with better handling in a true bolt-on scenario. The questions that usually follow include "whose springs to use?" and "what shocks work with said springs?" and so forth. However, the folks at Hotchkis Sport Suspension have done the homework for you and have devised a complete suspension package that will improve handling and create a safer driving environment with more control and predictability.

Hotchkis is known for its performance enhancing suspension offerings for newer vehicles, including the '79-'13 Mustang. Hotchkiss has now taken their Total Vehicle System (TVS) approach to '65-'66 Mustangs (and '67-'73 by the time you read this); giving the owner a suspension upgrade that will have your Mustang at home on your favorite winding road or at an autocross/track day event. Hours of track testing has ensured that the TVS package will improve your Mustang's handling measurably. The TVS package (PN 80040-1, $1,461.95) includes Sport coil springs with a 700 lb/in spring rate and Sport leaf springs with a 180 lb/in spring rate. The springs lower the Mustang for better handling by lowering the center of gravity without affecting ride quality. A larger 1¼-inch front sway bar and a 7⁄8-inch adjustable rear bar (both tubular steel) are included to help control body roll. Pairing a new suspension with upgraded shocks is a smart idea and Hotchkis-tuned SPS shocks by Fox Racing are available (PN 79020016, $550.95) to keep the suspension and tires planted. The SPS shocks feature aluminum mono-tube bodies, large ½-inch diameter shafts, and specially formulated oil and nitrogen gas for a great ride. All Hotchkis parts are made in the USA. The installation is designed to upgrade your Mustang in a single afternoon (it took us about five hours with photography) and, except for drilling two holes in your rear frame rails for the sway bar end link mounting, the system is a complete bolt-on and includes all new fasteners except for the front shock upper mounting bolts and the rear leaf spring front eye bolts.

1 With the Mustang on jack stands and ready to go, use a floor jack under the lower control arms to take the pressure off of the front shocks and unbolt and remove the shock mounting bolts and then the shock mounting bracket.
2 Remove the front tires to access the lower shock retaining nuts. The outboard nut, shown, usually will require an open end wrench to free, while the inboard nut can usually be removed with a socket and long extension. Raising or lowering the jack a bit can often help with access.
3 Remove the shock tower reinforcement panel (the steel plate with the bump stop attached) for access to the spring. Since this in-progress Mustang project already had lowering springs in place, they pulled right out, but stock springs will require a spring compressor and utmost care to remove.
4 The new front springs from Hotchkis are powder coated for long life and great looks, and include new urethane upper spring seats. A quick loop of electrical tape around the seat and spring will hold it in place during installation.
5 Place the new Hotchkis spring into the shock tower, ensuring it is centered over the spring locator at the top of the shock tower. Raise the suspension back up with the floor jack to seat the lower portion of the spring into the spring seat on the upper control arm. Before you put too much pressure on the spring, check to verify the spring’s “tail” is up against the spring stop in the seat, as can be seen here.
6 The optional SPS aluminum shocks are designed in concert with the TVS suspension system and we opted to use them in this suspension upgrade. You can see in this comparison shot of the typical front shock how much beefier the mounting base is, reducing flex and helping the shock do its job.
7 The Hotchkis/Fox shocks are real works of art with ½-inch diameter shock shafts, aluminum bodies, and heavy-duty mounting ends, yet they are direct drop-in replacements.
8 After lining up the lower mounting and securing with the included hardware, the upper shock mounting bracket is returned to its original location and the upper shock mount attached with the original hardware.
9 Moving on to the front sway bar installation, the included urethane sway bar bushings are greased with the provided tube of marine-grade lubricant to prevent squeaks and slipped over the sway bar.
10 Position the sway bar mounting brackets over the bushings and loosely attach them to the sway bar mounting tabs on the front frame rails as shown using the provided new hardware.
11 The sway bar end links are installed next. We found it best to assemble one side, compressing it slightly with a pry bar (between the frame and the top of the end link bolt), then start the retaining nut a few turns before doing the same for the other end link. Finally, center the sway bar and tighten the mounting brackets followed by the end links until the end link bushings have seated and compressed slightly.
12 The completed sway bar installation finishes the front suspension upgrade. Go over all of your fasteners one more time, reinstall the shock tower reinforcements, and put the front wheels back on.
13 Moving on to the rear, we have the chassis supported on jack stands, a floor jack under the axle housing, and the rear tires removed for access to the frame rails. The rear shocks are unbolted from the shock plate to get us underway.
14 With the bottom shock hardware removed and the rear axle assembly supported with a floor jack, the shock plates and U-bolts are removed from the axle and leaf springs. Severely corroded hardware may need to be cut off. New U-bolts are provided in the kit.
15 The rear shackle assemblies are added to the old parts pile next. Remove the shackle attaching hardware and pull/pry the shackle free from the leaf spring eye and the frame rail. Again, severely corroded suspension hardware may require cutting and/or heat to extricate.
16 The last removal step for the rear suspension is the leaf spring front eye bolt for each spring. This is most often seized to the bushing inner sleeve in the spring and will not easily come out. We were lucky in that this fastback spent its whole life in a southern climate, but you may not be so lucky. Seized eye bolts will usually require a reciprocating saw to cut through the bolt on each side of the spring eye. If so, you’ll need new spring eye bolts, naturally, and these do not come in the Hotchkis hardware kit.
17 A quick comparison of the stock leaf springs (bottom) with the new Hotchkis leafs (top). The Hotchkis leafs feature reverse spring eyes front and rear (to aid in lowering the rear of the car) and utilize a 4½-leaf spring pack.
18 The new leaf springs require new bushings for the rear spring eyes. These urethane bushings are included and simply need an application of the supplied grease to be pushed into the spring eyes. The metal bushing sleeve is installed last and a large C-clamp will help in seating the sleeve.
19 Due to the longer attaching hardware of the included shackle kit, it is necessary to install the upper shackle bolt with the outboard bushing and bushing sleeve in place on the bolt as shown here. Install the new leaf springs by lining up the front spring eyes with the frame holes and installing the eye bolts, then lift the leaf springs into place and secure to the new shackles. Leave all fasteners “snug” for now.
20 While the Hotchkis TVS hardware includes new U-bolts, due to the fact this ’66 had a 9-inch Versailles axle conversion, we had to re-use the U-bolts that came on the car. This is also a good time to upgrade to beefier spring plates with tie-down hooks too (found through your favorite Mustang vendor).
21 The rear shocks are direct replacement pieces, just like the fronts. The upper shock shaft is guided into the shock mounting hole in the body’s transition panel and then the shock is compressed by hand until the lower shock mounting stud can be inserted into the shock plate.
22 Traditional shock hardware is typically a double nut configuration—thread the first nut on and tighten, then lock the nut down with the second nut. Hotchkis uses nylon lock nuts instead. Due to the location of the upper shock mount, it is impossible to hold the shock shaft with an Allen wrench, as designed. The easiest way to tighten the upper shock mount is with an impact tool, such as the battery powered 18-volt wrench being used here.
23 The lower shock mount can be tightened next. Due to the lower mount being integral to the shock body, it is easy to prevent the shock body from rotating while tightening the nylon lock nut with hand tools.
24 The last piece of the rear suspension is the sway bar, and this is the only part of the whole TVS kit that requires modification to the car. A single mounting hole needs to be drilled in each rear frame rail to attach the sway bar’s end links (common to most any rear sway bar install). Using the outboard mounting plate as a template, scribe the hole to be drilled on the inside of the frame rail.
25 Start with a 1/8-inch drill bit to create a pilot hole and then drill the frame rail hole out to ¾-inch. This only needs to be done for the inboard side of the frame rail.
26 The inboard mounting bracket includes a ½-inch ID anti-crush tube for the frame rail. Slip the bracket’s tube into the hole you just drilled and secure it to the frame rail with a clamp. Use the anti-crush tube as a drill guide to drill a ½-inch hole through the outboard side of the frame rail.
27 Using the instructions as a guide, place the proper washers in order over the sway bar end link attaching bolt and end link bushing, and insert the assembly into the frame insert and secure with the outboard mounting plate and locknut with washer. Just snug the fastener for now, as everything will be tightened later with weight on the rear suspension.
28 The rear sway bar features three mounting points to adjust the bar stiffer or softer. In a nutshell, the farther the end link is away from the sway bar bushing mount on the axle, the softer the bar is. The instructions state to start with the middle hole for mounting and if you want to increase stiffness move the end link towards the axle. For a softer rear bar, move the end link away from the rear axle.
29 A second set of hands is always helpful, but in a pinch you can use your floor jack to support the rear sway bar while the end links are loosely installed into the middle hole on each end of the sway bar.
30 The sway bar mounting hardware includes a pair of U-bolts to secure the brackets to your axle. Be sure to place the U-bolts under any brake lines on the axle tubes. Alternatively, you can weld the steel brackets onto the axle tubes directly. When tightening the U-bolt hardware, ensure the mounting brackets stay parallel to the ground.
31 Once the axle brackets for the rear sway bar are tightened, the upper and lower end link fasteners can be tightened with the weight of the vehicle on the suspension by using your floor jack to raise the rear until the body just starts to come off the jack stands. Now is the time to tighten the front and rear leaf spring hardware as well.
32 Rolling the fastback outside for a quick photo op, the ride height is much better in the rear now, though about the same in the front since admittedly the fastback did have lowering springs on the front already. The new coil springs will take a bit of time to settle and the owner will see a little more drop once the rest of the vehicle’s weight is in (transmission, glass, interior, exhaust, etc.).