The easiest DIY suspension
modification on a 993 would be shocks,spring and sway bar upgrades. If you are just
replacing the shocks or springs the only special tool you will need is a spring
compressor. If you are replacing the complete coil over unit and the new unit come
already assembled you will not need to use a spring compressor. A 4 wheel alignment
would be necessary once everything is put back together.
Important note before you begin this
DIY The shop manual does recommend using a "half-open socket
wrench" made by Hazet to remove the shock piston bolt. And it does say "DO NOT
under any circumstances" use an impact gun to loosen or tighten the bolt.
I used the impact gun in my DIY because (1).
I do not have this special open socket wrench, (2). I have been using this impact gun
method for years without any problem. (3). Through hands on experiences I have had I can
pretty much apply the correct torque setting free handed. .......Although I own three
different torque wrenches...
For first time DIY people I do
recommend that you purchase the right tool prior to this DIY, the danger of using an
impact gun to tighten the top shock nut is that you might apply too much torque and strip
the thread the also break the shock shaft.
Here is a picture of how the
tool operates. The shock is secured onto the top perch by a 21 mm bolt that is
threaded to the center shaft of the shock. The shaft will rotate freely if you try
to tighten the 21 mm nut, so the half open socket allows you to use a 7 mm allen tool to
secure the shaft while the 21 mm nut is being tighten. The Hazet half open 21mm
socket is part number 2593, Hazet also makes a special 7 mm allen key with handle that is
part number 2593-1
suspension change(1). First you
will need to jack the car up and remove the wheel. You can either jack the whole car
up on 4 jack stands or just do one axle at a time.
(2). Remove the brake line
clip that is on the shock. At this time you will want to modify the brake line
holder with a Dremel tool so that there is an opening for the brake line to slide out
from. I found by doing this to be much less time consuming since you don't need to
bleed the brakes afterwards.
(3). unclip all the wiring
from the brakes sensor, ABS sensor to the round harness, and move the round harness away
from the shock at the right side and the back of the shock.
(4). (You will only need to do
this part of the procedureif you are installing new springs or shocks only.) Loosen
the large 21 mm bolt on the center of the shock near the shock tower. But do not
take the bolt out completely. ONLY LOOSEN IT. I used a impact
gun to do this, if you don't have a impact gun you will need to get a special Hazet half open socket tool that will
allow you to stick a hex key down to the center of socket to hold the shock shaft while
you loosen that nut. Or you can ask someone with a strong grip to hold the shock
shaft in place to prevent it from spinning while you loosen the bolt.
(5). Loosen and remove the
two bolts that secure the shock to the hub assembly. These are two completely
different size bolts, one is a 10 mm allen bolt the other is a 17 mm bolt, so there is no
way to put them back in incorrectly. The 10 mm allen bolt is used for camber
adjustment, while the 17 mm bolt is to secure the shock from moving after the camber
adjustments are made. After you have installed the replacement shock and before you
tighten the these two bolts you will need to push the top part of the hub assembly
including the rotor all the way inward toward the car to give yourself the maximum
negative camber, since there is no way for most people to set the correct camber without
the right tools. This is the only way to ensure that the camber is matched on both
side of the car before you drop it off at an alignment shop. Of course you could go
the other way of maxium positive camber instead.
(5). Loosen the four
13 mm bolts at the shock tower that holds the shock assembly to the shock tower. At
the time the shocks will come off the tower and the hub by pushing down on the hub
assembly. Make sure you remember the direction of the red marking on the rubber
shock perch. When reinstalling the shock it needs to point back at the same
direction. And you should ask someone to hold on to the shock assembly from below
before you loosen all the nuts. In most cases the shock assembly will just
(6). Since in this project
the shocks will be replace with a Koni adjustable shock so the plastic wire clips and wire
harness mounts must be transferred over to the koni shocks. You will also want to
modify the brake line holder on the Koni shocks so the brake line can be installed back.
(7). Now is also a
good time to put the two shocks next to each other and make a comparison and make sure the
replacement shocks looks exact the same as the factory shocks.
(8). Install the
spring compressor on the factory spring to hold the spring in place while you remove the
large bolt on the top center of the spring perch. (Where I used a impact gun to remove
the nut) Once the large but is removed you can remove the shock perch from the
factory unit and install it on the new unit with the new spring. Again here is where the special Hazet half
open socket will come in handy.
(9). Install the new shock+springs
back in the shock tower, and hand tighten the four 13 mm bolt on the shock tower. At
this time you will need to modified the original factory shock bolt (that bolts the shock
to the hub assembly) holder if you are replacing the factory shocks with a Koni adjustable
(10). Reinstall the 2 shock
mounting bolts, you will need to get a floor jack underneath the hub assembly to jack up
the assemble a little at a time to get the shock to line back up with the hub
assembly. It takes some time to line them up, but once they are lined up you can get
the bolts to go through with ease. Tighten the shock mounting bolts and tighten the
four 13 mm shock bolts on the shock tower.
(11). Reinstall all the
wiring harness and clips. Slide the brake line back to the brake line holder on the
shock. You are done!
Click here for the
here to see the installation of the RS Clube Sport mono ball coil over units on Hank's 993