Tech / Tech Projects

Surefooted Steed: Adding a RideTech Coilover Suspension System to Our ’68 Mustang

 

 

In the real world, sometimes life and unforeseen issues cause a project to get off course and backburnered for a bit. It’s probably happened to you, and it happened to us with our ’68 Mustang build. One of the biggest hold-ups was the necessity of replacing the framerail and lower core support on the passenger side forward of the front tire. Battery acid had literally eaten a hold straight down through to the ground and left that whole corner a rusty mess. Luckily it was non-structural and easy to isolate, but the problem was finding a shop we trusted, and of course paying for the work. It all worked out in the end and now we’re back on track and ready to make progress again. Next up; suspension.

If you remember our last installment when we swapped in a T5 5-speed trans in place of the C4 automatic using Summit Racing’s new swap kit, one of the main reasons for doing so was the joy of driving. Well, by far the biggest impact on the driving experience comes from the choice and condition of the suspension under the car, and our Mustang’s was stock and sloppy. Most of it was original and high mileage, and even the few replaced bits were essentially shot. It was drivable, but it really felt like an old, worn out car. That would never do since the owner of this particular project wants to get back out and enjoy it on the open road.

While we would like to get the Mustang up to basically modern handling standards, we also really want to keep it to a mostly bolt-in affair, so no MII style suspensions. What we wanted was something that took advantage of the good points of the suspension, but also took time to engineer out the shortcomings as much as possible. One of best solutions we found was via RideTech’s CoilOver System for ‘67-‘70 Mustangs. The system is a complete front and rear package that includes their HQ Series CoilOvers, front upper & lower tubular StrongArms, a MuscleBar anti-roll bar, and a 4-link conversion for the rear. The front is almost a complete bolt-in affair with only minimal work required. The rear is a bit more involved, and does require some welding, but after speaking with RideTech technicians and reading through the instructions, we were convinced that it was a task we could take on.

While we’re opting for the simplicity of coilovers, the systems also support RideTech’s air ride options, if you’d like the ability to tuck the tires way up in the wheel wells while at a show. For us, we just want to get the improved dynamics that RideTech engineered into the system. While it should comfortable for long distance drives, which is important since road trips and cruises are in the cards, the higher spring rates and performance valving in the RideTech shocks will also make our Mustang a much more capable performer- something which we’ll be testing down the road.

For now, we’ll show you exactly what involved with getting it installed.

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We’ll spare you the boring and tedious disassembly pics, but we did want to show you what our ‘68’s highly worn front suspension looked like. Ball joints and bushings have been replaced a couple decades back, but everything is now highly worn and sloppy.

Check out this distorted and near disintegrated lower control arm bushing. Note that the control arm has actually shifted to one side.

While Ridetech’s fronts suspension is a bolt-in design that uses the same factory attachment points, the tubular upper and lower Strongarms have a lot of geometry changes built into them. For example, the billet cross shaft on the uppers uses the original mounting location, but has a built-in Shelby drop.

A standard 4-bolt mount upper ball joint is utilized, but the plate it sits on features revised geometry to make the most out of the Shelby drop and lowered ride height.

The Ridetech tubular lower control arm combines the factory style lower control arm and adjustable strut rod into one unit that will inherently have less flex and greater strength.

Rather than squishy and disintegrated rubber, we have urethane bushings at most attachments points of the Ridetech kit that will firm things up without transferring too much NVH.

The upper arm bolts to the unibody using ½ x 2 ½ bolts, flat washers and lock washers. A shim is supplied and may need to be installed between the body and the arms to achieve proper alignment. The arms are preset at the factory so the alignment should be close, but we’ll still need an alignment before driving. By the way, the upper arm mounting holes on many cars have been redrilled 1-inch lower for the Shelby drop, but since the Strongarm cross shaft has the drop built into it, make sure to use the higher factory mounting holes.

Using the bushing retainer as a template, mark the holes to drill with a center punch. This metal is rather thick, so we recommend a pilot hole and then stepping up a couple of sizes to get to the final 3/8 bit. Make sure you have sharp drill bits or this will be a very tedious and time-consuming job.

Place the spherical bearing inside the bearing housing, then clamp it to the frame with the bearing retainer and the 3/8” x 1 ½ SHCS and lock washers

That’s where this nicely milled piece of billet comes in. This will slide right up over the coil spring ring and provide an upper mount for the coilover.

This plate takes the place of the stock upper shock mount and clamps the lower billet piece to the tower with three 5/16 x 1 bolts.

We’ll spare you the coilover assembly as the Ridetech manual does a great job of explaining how the upper shims and bushings go together. Once assembled, the upper stud of the coilover slides through the upper mount and the bottom attaches to the upper arm.

It’s antiroll bar time- or MuscleBar, as Ridetech calls them. These thick bars were developed specifically for lowered vehicles and use polyurethane bushings with new brackets.

There’s only so much tech in a bar, but these Posi-Link endlinks are quite trick for a vintage muscle car. Versus the standard style bushings sandwiched around a bar, the Posi-Links are a much stronger design with better transfer of motion through swaybar without deformation or binding. This lets the bar do the work it’s intended to do more effectively.

While you might be thinking rack & pinion swap, Ridetech has actually found that the Borgeson power steering box conversion works best with the stock Mustang spindles and their suspension. That’s fine with us since it’s direct bolt-in swap that just uses stock manual steering components vs. power. There are some exhaust considerations when swapping to a 351W, so we’ll get into those details in our next engine installment.

Our rear suspension consisted of a set of mid-eye leaf springs with poly shackle mounts and generic shocks connected to the Currie 9-inch. A decent basic set-up, but one not well matched to the capabilities of the RideTech front suspension.

Here’s the foundation for the RideTech rear suspension; a cradle that will tuck up tight to floorpans and connect the framerails together to create strong mounting points while stiffening the rear chassis.

Before that can happen, we do have to do a bit of cutting. The bulge that holds the pinion snubber needs to be cut off flush to the floorpan. Luckily this is a spotwelded on piece, so there is floorpan underneath it.

On our car, this mounting tab for the rear brake line also needed to be removed by drilling out the two spot welds. The fuel line will also need to be removed.

The tolerances on 1960s cars in general is pretty loose, so we were quite pleasantly surprised to see that the cradle fit very closely. We have a few holes to drill, so by using a screw jack to hold the cradle in place, it serves as our locating template for marking our holes.

The holes are grouped in pairs because the cradle is held in by these 3/8 square u-bolts. After marking our holes we dropped the cradle and used a punch to create a divot for our pilot holes. These large bolts need a 7/16 hole, while the three front ones on each side need a 5/16.

The square U-bolts are installed by inserting one end into one of the drilled holes and then using the other end as a handle to fish it through and locate the other hole.

While bolting in is technically all that is required, we are opting to lay a few beads of weld at strategic places to increase overall rigidity. Here Steve uses a wire wheels to bring the spots to bare metal.

With the cradle pressed back into position with the crew jack, each u-bolt gets a 3/8 washer and nylock nut on each end. Just snug them down until all are installed, then come back and tighten.

Here’s the cradle nearly fully installed. It’s easy to see how this will serve to greatly stiffen up the rear framerails.

We opted to drill the front three holes last with the rest of the cradle solidly in position.

With all of the bolts fully torqued into place, we’ll come back and lay a bead of weld inside this gusset as well.

The LCA axle bracket is quite straight forward, since it bolts directly to the leaf spring perch on our Currie 9-inch. The billet bracket on the rear is our attachment point for the coilover. The LCA itself slides right into the front leaf spring pocket and then bolts to one of the three mounting positions on the axle bracket.

Here’s the only somewhat tricky part of the install; welding on the upper control arm mounts. This two piece mock-up arm is included in the kit and preset to the correct length. One end gets bolted into the UCA mount on the cradle.

The other end is bolted to the two tabs that will form our mounting point on the rearend. If you have a stock housing, this is a bit more straightforward as the tabs are cut to sit on the axle tubes. Our Currie 9-Inch has a much larger and stronger center section, so we’ll need to alter our tabs while maintaining the RideTech geometry.

We made some templates with cardstock and bolted them to the mock-up arm. We carefully cut them to fit the shape of the housing while being sure to maintain the correct position for the arms. The height we want to achieve is 3.5 inches from the axle center line to the center of the bushing.

Here are the finished tabs. Note that we wrapped the weld around the ends of the tabs to avoid creating a stress point.

On the ground with the coilovers in place you can easily see one other required modification when running the RideTech 4-link rear suspension; the stock rear tailpipes will no longer fit and there isn’t much hope of routing customs ones either. The best options are side exit exhaust, turn downs off the mufflers, or you could follow our plan and route the tail pipes under the housing. Ground clearance will not be an issue, we just have to determine clearance for travel.

The stance is spot-on perfect for now, and when things change after the we get the full weight of the drivetrain and interior in the car, getting it back up to the right height will be as simple as adjusting the Ridetech coilovers.

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One Comment

  1. Andrew Pentland says:

    What wheels are those size type and tire please

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