Loosen the wheel nuts, then lift the car and support it on jack stands; see either the Maintenance section from Tips from the Garage Web page, the Mazda Shop Manual, or the Enthusiast’s Manual for further details. I found that a good light source was often helpful, and that lifting the car within range of a shoplight and it’s extension cord was good insurance (if the car is lifted outside, and the wheels are off, it gets dark, and you’re not finished, that might be a bit inconvenient - not that it happened to me, of course). Remove the wheels.
2. To access the rear shocks, In the boot first remove the metal guard that protects the fuel lines (left shock) and the spare tire (right shock). Loosen the shock absorber upper shaft nut a few turns (it’s more difficult to do this after the unit is out of the car) with a 17 mm socket and extension, but DO NOT completely remove the bolt, or the spring will separate from the shock (which is dangerous, and probably impossible to rectify once it occurs).
3. Remove the upper mounting plate nuts with a 14 mm socket and extension. Be careful not to drop the nuts into the sheet metal around the upper mounting area, or they’ll wedge into place against the body in a very tight area (especially the rear one).
4. Disconnect the sway bar’s attachment to the lower A-arm linkage (14 mm socket), to allow the A-arm to swing out of the way in subsequent steps. The sway bar can be removed either where it joins the A-arm, or at the point between the main (horizontal) sway bar and the curved link that fastens to the arm. I suggest the latter approach - it was very difficult to reattach the bushing to the lower A-arm, much easier to reattach between the main sway bar and the A-arm link.
5. Remove the lower shock mounting bolt (and keep track of which way the head of the bolt is pointing so that it can be replaced in the same configuration).
6. Remove the bolt that joins the upper A-arm to the wheel hub (and again, keep track of how the bolt should be replaced). This allows the wheel hub to swing downward, freeing up the shock/spring assembly, and allowing for easy removal. There is a paint mark on the spring that should be used to return the spring to the same position after the unit is replaced (if the shocks are to be replaced and the old springs reused). Alternatively, place a piece of tape, paint, or otherwise mark the spring to allow for reorientation.
7. Recover the top mounting gasket (a thin, white plastic gasket between the top mounting plate and the frame).
8. Clamp the shock in a vice (if they’re going to be replaced, no need to worry about damaging them in the vice; otherwise, protect the shock with wood or aluminum sheets placed between the shock and the vise jaws), and attach spring compressors. Compress the spring until the top mounting plate is loose, and the spring can rotate independently of the shock. Remove the top shaft bolt (loosened in Step 2), the mounting plate, and the compressed spring.
9. Protect the replacement (or re-used) shocks in the vice as noted above, and reassemble the compressed spring over the shocks (if new springs are to be installed, then decompress the old spring and discard (sell?), then compress the new spring). Place the top mounting plate over the shock/spring unit, and replace the top mounting bolt. Make sure the unit is aligned correctly, with the spring seated properly against the shock absorber and the top mounting plate, then reinstall in the car. Use the OEM paint marks or your marking tape, etc. to replace the spring in the same orientation that is occupied prior to removal.
10. Lubricate the lower shock mounting bolt with molybdenum or similar grease, and replace the bolt. Lift the wheel hub and replace the bolt joining the upper A-arm to the wheel hub (a short piece of wood to support the hub or a helper is nice; a little grease also can be used to lubricate the bolt). Make sure the plastic gasket is replaced on top of the mounting plate and thread the upper mounting plate bolts through the chassis holes. Loosely reattach top mounting nuts, and replace the sway bar linkage bolt/nut. Re-torque all nuts/bolts to specifications (see below), and replace wheel, spare tire, and metal trunk guard.
11. From inside the engine compartment,
Loosen the shock absorber upper shaft nut a few turns, but DO NOT completely remove the bolt (see items 2 and 3, above). Remove the upper mounting plate nuts with a 14 mm socket and extension.
13. Disconnect the sway bar to the links on both sides (this will allow the lower A-arm to drop sufficiently in subsequent steps). Again, remove the sway bar at the point between the main (horizontal) sway bar and the curved link that joins the A-arm - this is the easiest point to reattach the sway bar.
14. Remove the lower shock mounting bolt. As above, remember/record the original orientation of the bolt and nuts. In ABS-equipped cars, a wire will be attached to the shock via a welded clip. Carefully pry the clip away from the wire with a large flat-bladed screwdriver and remove the wire from the shock absorber.
15. Carefully step on the lower A-arm (it now can go down about 3-4 inches) and pull the top of the shock towards you (i.e., to the outside of the car). This provides enough room to attach a spring compressor while the spring/shock assembly is still on the car. Note the orientation of the OEM paint marks on the spring, or add your own paint or tape to indicate the original position of the spring, as noted above for rear shock absorber installation. Then carefully compress the spring.
16. Push down on the upper mounting plate (compressing the shock; the spring is already compressed) and remove the mounting plate. This provides another few inches of access. Save the white plastic mounting gasket.
17. Again push down on the shock piston rod. This should provide enough room to move the top of the shock/spring towards you, then up and out of the car, while a helper steps on the lower A-arm (it’s more difficult, but possible, to do it as a one-person operation). If the shock becomes stuck in the lower mount, then gently prying it free with a large flat screwdriver may be helpful before the final removal.
18. Replace the shocks and/or springs as noted above in #8 and 9, but leave the spring compressor attached to the (compressed) spring. Reinstall into the car by reversing the above procedure: step on the lower A-arm, and slip the unit back into place.
19. Lubricate the lower shock mounting bolt with molybdenum or similar grease, and replace the bolt. Push down on the shaft of the shock, and replace the top shock mount. Replace the nut holding the shock absorber shaft to the mounting plate.
20. Push down on the lower A-arm, and align the top mounting plate bolts in the holes in the chassis, and replace the mounting plate nuts. Decompress the spring and remove the compressor. Then replace the sway bar linkage bolt/nut, and re-torque all fasteners to specifications
21. For ABS-equpped cars, net.suggestions for reattaching the ABS wire to the shock have included: a) ignore it; it’s just to stabilize the wire a bit, it’s not rubbing against anything, and there are two other mounts; b) fabricate a mount from a metal strip, and epoxy it onto the new shock; and c) secure it to the shock with a plastic cable tie.
22. Replace the wheel, and retorque the nuts as noted below (or to your specs).
23. Road test
Torque Specifications (from the Mazda Shop Manual)
Sway bar links: 36-54 N-m (27-40 ft-lbs)
Lower shock mounting nut: 73-93 N-m (54-69 ft-lbs)
Upper shock mounting nuts: 29-36 N-m (22-27 ft-lbs)
Rear upper A-arm to wheel hub bolt: 46-67 N-m (34-49 ft-lbs)
Wheel nuts (OEM): 88-118 N-m (65-87 ft-lbs)
Shock piston rod upper nut: 29-36 N-m (22-27 ft-lbs)
Rear shock, first time, no clue: about 4 hours.
Rear shock, second and subsequent time: about 1-1.5 hours for both.
Front shock, after benefit of replacing rear shocks: about 1.5-2.0 hours for both.