Mark Houlahan
Tech Editor, Mustang Monthly
January 24, 2014
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.).