Honda CR-Z (ZF1) Lowering Spring Installation
Introduction
This guide covers fitting aftermarket lowering springs to the Honda CR-Z (ZF1), replacing the factory coils with a shorter, stiffer set such as Swift, Eibach or Tein to cut ride height and reduce body roll. The front struts are coilover-style units that must be taken apart on a strut spring compressor, whereas the rear springs sit separately from the dampers and usually need little or no compression to swap. A theme that runs through the whole job is the bump stop: once the car settles lower the factory bump-stop gap closes up, so many kits call for trimming the stops to keep suspension travel and ride quality intact. Always follow the specific spring maker's instructions on whether the front, rear, or both need trimming, since it varies by kit and car. Plan on roughly two to three hours with air tools, or most of a day working by hand. On a CR-Z fitted with Swift springs, ride height measured from the ground to the fender fell from about 655/660mm at the front and 665/670mm at the rear to 625/630mm front and 636/640mm rear. Adapted from a community writeup by AlexS2200 on CRZ Forum (https://www.crzforum.com/threads/diy-lowering-springs.3215/), including corrections from the follow-up discussion.
Reference
Tools Required
- Floor jack and jack stands
- Socket set with 12mm, 14mm, 17mm and 19mm sockets
- Open-end wrenches in 14mm, 17mm and 19mm
- Breaker bar
- Hex (Allen) key set for the strut shaft bolts
- Strut-type spring compressor (clamps the outside of the spring)
- Flat-head screwdriver
- Utility knife or razor
- Rotary tool with cut-off wheel, or a chisel, for the rear crimped sleeve
- Saw or blade to trim the bump stops
- Torque wrench
- Zip ties
- Air or impact tools (optional, greatly speeds the job)
Parts Required
-
Aftermarket lowering springs (e.g. Swift, Eibach Pro Kit, Tein)
-
Reused factory rubber spring grommets/isolators
-
Replacement rear crimped sleeves (included with some kits such as Eibach) or tape/plastic weld to reseal the rear dust boot
Safety Warnings
- ⚠ Always support the car on jack stands. Never work under a vehicle held up by the jack alone.
- ⚠ A compressed strut spring stores dangerous energy. Use a proper strut spring compressor and confirm it is fully seated and the spring unloaded before removing the top shaft nut.
- ⚠ Put a floor jack under the rear lower spring seat before loosening the rear damper top nut; without it the nut and mounting washer can be ejected under spring load.
- ⚠ The front CV axle can pop out of the hub when the strut is dropped. Secure it with zip ties or a helper, and note that if the internal bearings dislodge from the boot the repair becomes much larger.
- ⚠ Have a wheel alignment performed after installation, as lowering springs put the toe out of specification.
Step-by-Step Instructions
1 Lift the car and remove the wheels
Crack the lug nuts loose while the car is still on the ground, then raise it at the factory jack points and set it securely on jack stands at all four corners. Remove the road wheels with a 19mm socket to expose the strut and hub assemblies.
2 Disconnect the front brake line and ABS sensor
At each front corner, unbolt the brake hose bracket from the strut body using a 12mm socket. Unclip the ABS wheel-speed sensor lead and free its rubber grommets from the strut so the line and wiring can hang clear without strain while the strut is removed.
3 Separate the front strut from the sway bar and knuckle
Detach the sway bar end link from the strut with a 14mm wrench; without air tools you may need to hold the ball-stud with a hex key while turning a 14mm open-end wrench. Then remove the two 19mm strut-to-knuckle bolts with a 19mm socket, using a breaker bar and a 19mm open-end wrench on the nut to stop it spinning.
4 Release the top mount and drop the front strut
Pry the rubber cap off the top of the strut tower to reach the upper mount nut. Hold the strut shaft with a hex key and loosen the top nut with a 17mm open-end wrench. With the top nut off, the strut assembly can be worked free and lowered out through the bottom.
5 Disassemble the front strut on a spring compressor
Mount the strut in a proper strut spring compressor and compress the coil until the top mount is fully unloaded. Only then remove the 19mm shaft nut, lift off the top hat and upper seat, and take out the stock spring. Keep the parts in order for reassembly.
6 Trim the front bump stop if required
Pull the bump stop off the shaft. If your spring kit specifies it, shorten the bump stop by about 25mm (1 inch). The reason: at stock height roughly one inch (25mm) of clearance separates the stop from the strut body, but lowering closes that space entirely, so an untrimmed stop ends up resting on the strut, ruining compliance and causing a harsh ride with heavy understeer. Some kits require this front only, some front and rear, so defer to the spring instructions.
7 Reassemble the front strut with the new spring
Fit the new lowering spring, reinstall the bump stop, upper seat and top hat, then torque the shaft nut back down before releasing the spring compressor. Refitting the bump stop into its rubber cup is fiddly; seat it in the cup first, place the whole assembly on the shaft and press it home. A little lubricant helps it pop into place.
8 Reinstall the front strut and watch the CV axle
Refit the strut in reverse: top mount first, then the two knuckle bolts, the sway bar link, and finally the brake line and ABS sensor. As the strut drops and the knuckle swings out, the front CV axle can pop out of the hub. Secure it with zip ties or an extra pair of hands. If it does pull out, jack up the lower control arm and gently work the axle back and forth to reseat it.
9 Access the rear top mounts
Inside the boot (trunk), gently pry back the left and right rear side trim panels with a flat-head screwdriver to expose the rear damper top-mount nuts. These are hidden behind the plastic panels rather than under a cap like the front.
10 Remove the rear shock and spring
Before loosening anything, place a floor jack under the lower spring seat or control arm to catch the load. Loosen the rear top-mount nut with a 14mm open-end wrench and a hex key on the shaft, then remove the lower shock bolt from the subframe with a 14mm socket. The lower arm drops, letting you take out the shock and lift the stock spring off the subframe. Work both sides together on the rear.
11 Deal with the rear crimped sleeve and bump stop
The rear shaft carries a factory sleeve/washer that is crimped with a locking indent and cannot simply slide off without damaging the threads. Choose one method: carefully cut or drill through the sleeve above the indent with a rotary tool and cut-off wheel, split its seam with a chisel, or slit the dust boot open with a razor to reach the bump stop. Eibach kits supply new replacement sleeves so nothing needs taping or gluing back together. Trim the rear bump stop by about 25mm (1 inch) if your kit calls for it, then reseal or replace the boot/sleeve.
12 Fit the new rear springs and reassemble
Transfer the factory rubber grommets to the new springs. Seat the new springs on the subframe; they generally need very little compression, so most installers just push down on the hub or use the lowered lower arm to gain clearance rather than a compressor. Reinstall the shocks, thread the top nut and washer from inside the trunk, and refit the rear trim panels.
13 Reset ride height and get an alignment
Lower the car, torque the wheels, and let the springs settle over a few days of driving; expect only a few more millimetres of drop. Because lowering pushes the wheel toe out of specification (camber usually stays acceptable), book a wheel alignment afterward to protect tyre wear and restore handling.
Pro Tips
- 💡 With air or impact tools the job runs about two to three hours; by hand it can stretch to six or more, mostly from fighting the stubborn hex-head strut bolts.
- 💡 The rear springs need very little compression, so many installers skip the compressor entirely; compressing the OEM springs once, however, makes that first removal safer and avoids stressing the trailing-arm bushing.
- 💡 For the rear crimped sleeve you have several options: drill or cut it off with a rotary tool, split the seam with a chisel, or slit the dust boot with a razor. Eibach kits include fresh sleeves.
- 💡 Tie rods do not need to be disconnected for this install.
- 💡 A strut-type spring compressor clamps the outside of the coil, unlike a hooked coil compressor that grabs the inside; the strut type is the correct tool here and can be rented from an auto parts store.
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