Before we begin, let's take...
Before we begin, let's take a second to measure the stock height so we can see how much this Eibach Pro-Kit lowers the car. The front wheel arch is 2831/48 inches off the garage floor at the peak. If you're wondering, the tires are about 2531/44 inches high, which means there's a 251/48-inch wheel gap.
If you're looking for even more drop, Eibach's Sportline springs will be available by the time you read this. The '05 may be all-new, but its design incorporates a number of traditional Mustang cues, including the jacked-up 4x4 look. HiTech chose Eibach's Pro-Kit springs because they improve handling while providing a moderate drop for a much better stance, without making the car too low to drive and enjoy. The dual-rate progressive design is what gives the Eibach Pro-Kit springs the best combination of ride quality and handling, with just the right amount of drop.
One thing everyone (even non-Mustang enthusiasts) can agree on is the fact the '05 Mustang has a distinctive look. Many people love it, some hate it, but most have a strong opinion one way or the other. The '05 may be all-new, but its design incorporates a number of traditional Mustang cues, including the jacked-up 4x4 look.
Lowering springs have long been at the top of the early mod list for most Mustang enthusiasts. Even for owners who don't modify their Mustangs for looks, the stance still has to be right. And if you're going through the trouble of lowering your Mustang, you might as well use some springs that improve the handling performance too, not just slam it to the pavement.
The lowering springs we'll be using for HiTech Motorsport's '05 GT come from Eibach Springs, one of the most well-respected names in suspension performance. HiTech chose Eibach's Pro-Kit because it provides a moderate drop for a much better stance, without making the car too low to drive and enjoy, and improves handling.
We called the guys at Eibach to get the skinny on the Pro-Kit springs. They explained that the front and rear Pro-Kit springs are dual-rate progressive, as opposed to being linear like the stock springs. The hardtop '05 GT's factory front springs are 136 lbs/in, while the Pro-Kit fronts have a 171-lbs/in initial rate and a 229 final rate. In the rear, the stock springs have a 142-lbs/in rate, compared with the Eibach rear's 109-lbs/in initial rate and 200-lbs/in final rate.
The gap in the rear is even...
The gap in the rear is even worse, at 3 1/4 inches. The peak of the rear fender is 29 inches from the garage floor. For all these measurements, your results might be slightly different, depending on the consistency of your garage floor and the pressure and temperature of your tires-not to mention that no two cars are exactly the same.
After you've taken off the...
After you've taken off the rear wheels and supported the rear axle, remove the bolts holding the top of the calipers. With the caliper bolts removed, you'll be able to lower the axle down without ripping the brake lines.
Remove the bolts holding each...
Remove the bolts holding each of the rear shocks to the rearend. Then, lower the axle to allow the springs to expand. If new rear shocks are in the cards, now would be a great time to install them.
Work the springs around and...
Work the springs around and pull them out. Simply slide the new Eibach springs into place the way the old ones came out. Put things back together the way you found them-hopefully there won't be any leftover parts. Don't fully tighten the rear shock bolt until the car is resting on the ground or you may get some bushing preload, which will hold the rearend up higher than it should be.
The stock '05 GT spring (right)...
The stock '05 GT spring (right) is linear, while the Eibach (left) is a dual-rate progressive design. This means the initial spring rate is softer, so it has some give for a comfortable ride. The final spring rate is higher, so when you really throw it into a corner, you get the better handling of a stiffer spring.
Moving on to the front, begin...
Moving on to the front, begin by unbolting the brake lines from the strut assemblies. You can use a 10mm wrench, as shown, or a 10mm socket and ratchet.
Using an 18mm wrench, loosen...
Using an 18mm wrench, loosen and remove the two bolts holding the spindle to the strut assembly. The spindles swing right out of the way.
Remove the bolt holding the...
Remove the bolt holding the end-link to the strut assembly, and move the end-link out of the way.
To get the strut/spring assembly...
To get the strut/spring assembly out of the car, you have to remove the bolts holding the strut assembly to the strut tower. Be careful when removing the last bolt, as the assembly will fall right out. Just loosen the bolt with one hand and hold the spring/strut with the other.