C4 Front Spring Removal

I have gotten lots of emails for this write up so I’m
dropping it in here also.
Front spring removal on a C4 Corvette
(This covers non adjustable suspensions. However adjustable suspensions
should be the same except the shock & actuator removal &
handling.)
NEVER PLACE ANY BODY PART UNDER OR NEAR THE COMPRESSED
SPRING! IF THE SPRING BROKE FREE IT COULD MAME, CRIPPLE, OR KILL YOU.
PERIOD! TREAT ANY COMPRESSED SPRING THE SAME WAY YOU WOULD TREAT A LOADED
GUN !
If you don’t have basic mechanical skill or don’t feel
confident/ comfortable with your mechanical skill level do NOT try to
remove the front spring.
Tools needed:
Jack Stands
(two)
Floor jack
1/4” ratchet (13mm deepwell socket) (6”
extension)
3/8” ratchet (15mm & 18mm deepwell sockets) (2 6”
extensions)
1/2” ratchet (22mm standard socket) (3”
extension)
13mm, 15mm, 11/16” box in wrenches
Small adjustable
wrench
1/4” to 3/8” adapter
3/8” to 1/2” adapter
Torque
wrench with a minimum range of 19 to 100 lbs/ft
Wooden ramps as shown
(or similar)
Two 1×4 34” long
Two 5’ lengths of 1/4” or
greater rope (poly or cotton)
Several lengths of 2×6 & 2×4 as need
depending on conditions.
A creeper would also be useful.
Before
starting this task you need to understand that the front of the car will
be very high off the front of the ground at times & extreme safety must be
used not only while the car is this high but also while raising/ lowering
the car from/ to the jack stands & while working around the spring. Also
while not necessary, I strongly suggest getting a pack of zip lock bags &
a permanent marker to help keep track of the bolts, nut, & washers & there
respective locations. Most of the parts you will be dealing with are made
of aluminum. Don’t use the jack with the jack head in direct contact
with any aluminum parts. The part can be damaged. If you are not
familiar with the way your floor jack works or if it is new practice
lowering the back or front of the car to get accustom to the jack.
Raising is no big deal but when unloading the springs & lowering the car
from a large height you will need to lower the jack head slowly to prevent
an out of control situation. This takes practice & you don’t want to
learn this skill doing this process. You will want to know where the
”break point” is in the jacks’ release valve so it can just barely
be cracked open & closed quickly if needed. If you are thinking this
sounds silly or stupid then you really need to go practice this technique.
The people who have this mastered know how important it is & that it will
change from jack to jack even of the same brand. I can not emphasize this
point enough. Know your jack. Know how its acts & how it reacts. OK now
I will get off of my soapbox.
Start by putting the car some place
level with solid ground under it (i.e. concrete or asphalt) The front
spring will need to be relaxed before removal. To do this the front sway
bar will need to be disconnected, the shocks removed, the lower control
arms separated from the rest of the suspension assembly, & the passenger
side lower control arm removed. Don’t worry its easy than it
sounds.
Back the car up into the wooden ramps so the rear end is
off the ground. Yes the back not the front. This will keep the cars’
geometry better for when the nose gets raised up. Block the rear tires so
they won’t move & put the car in 1st or park & set the emergency brake
real good. Raise the hood & make sure there is plenty of clearance between
it & any overhead objects.
Place the floor jack under the front
frame member with a wooden block between the jack & the frame of the car
to prevent the jack from scratching the frame. Raise the front of the car
just enough to relax the suspension. Brake the lugs lose on the front
tires & raise the car high enough to remove the front tires & place the
jack stands under the front frame rails of the car behind the front tires
(where the cross brace for the convertible attaches). Lower the car onto
the jack stands. The nose should be level or slightly higher than the
back of the car while resting on the jack stands
Unplug the wiring
to the speed sensors. The are in the back of the wheel bearings (two wire
clip connector). Move the speed sensor connectors out of the way so they
don’t damaged. Remove the lower bolts from the front sway arm linkage
to lower control arms on both sides of the car (15mm). The sway bar is
not under any pressure so it won’t go flying around, however you may
need to wiggle the sway arm to get the bolt out of the sway arm linkage.
Do both side of the sway bar at this point. Put the nuts back on the
bolts & set them to the side. If you have zip locks bags put the bolts &
nuts in a bag & mark it. I am not going to refer to the bags any more but
anytime a part comes off the car it should be placed in a bag &
marked.
Next place the floor jack under one of the control arms
just inside of the ball joint Again use a block of wood to prevent damage
to the lower control arm. (The control arms are made of aluminum & will
scratch & mar easily.) The jack should be in the same plane as the spring
with the nose of the jack toward the outside of the car & the back of the
jack under the engine. DO NOT TRY to raise the control arm with the jack
rolled in from the front of the car (facing front to back). The jack MUST
be parallel to the spring. The reason for this is because the extreme
pressures of the spring will side load the jack as it is lowered causing
the jack to flip over slamming the spring downward. Raise the control arm
about 2 inches. Remove the aluminum (or steel) block that hold the spring
to the frame (they are just in front of the motor mounts in the cross
member the spring runs through.) on the same side as the jack (also 15mm).
Now make sure the control arm has been raised so the shock is slightly
compressed.
DO NOT START THE FOLLOWING INSTUCTIONS IF THE JACK IS
NOT SUPPORTING THE SPRING & WHEEL ASSEMBLY. THE SPRING CAN BREAK THE
ASSEMBLY LOOSE WITH EXPLOSIVE FORCE DAMAGING NOT ONLY THE CAR BUT ANYONE
AROUND THE ASSEMBLY OR SPRING! Remove the cotter pin & castle nut (22mm)
from the lower ball joint. Break the lower ball joint loose from the rest
of the hub assembly. If you don’t have a ball joint separator (which I
suggest) use a 6” long 1/2” diameter brass rod or a 6” long 1”
dowel rod to tap the ball joint loose. Be very careful & do not use
anything made of steel. The assembly around the ball joint is aluminum &
could reform if steel is used to drive the ball joint out. Tap upwards on
the hub spindle where it meets the ball joint alternating between front &
back. Don’t get in a hurry if you do it this way. After the ball
joint is loose take the 34” 1×4 and place it across the top of the
fender well. Take the rope & tie the upper control arm/ hub assembly up
out of the way. Get it as height as you can. Make sure not it kink or
knot the brake line as you raise it up. After it is tied up remove the
top shock nut & washer (11/16” wrench & small adjustable wrench). Now
SLOWLY lower the control arm. It may help if a helper places a long 2×6
under the car & holds pressure against the back of the jack to keep it
from rolling out from under the spring or you can push against the jack if
you are strong enough. (I only weight 125lbs and the spring was pulling me
& the jack around. This keeps the spring from pushing the jack out from
under it as it is lowered. Look at it this way, when you first put the
jack under the car the springs force is primarily straight down (X
component for the physics guys) as the spring is lowered its force not
only diminishes but also transfers from vertical to horizontal (Y
component) because of the bow the spring. If the jack bottoms out you
should be able to pick up on the control arm enough to get the floor jack
out. Now repeat this process for the other side of the car. After both
sides are down remove the shocks from the lower control arms. The control
arms should both be floating on the spring & should be pointing down at
roughly 45(. The cross brace behind the passenger side rear lower control
arm bolt will need to be removed control arm bolt out. Remove the brace,
it has (2) 13mm bolts on the side frames, (2) 15mm bolts in the center
cross member frame, & (1) 18 mm bolt under the engine mount.
Next
check to make sure the spring is not under tension still by pushing down
on one of the control arms. If the spring is still under tension take a
small block of wood & place it horizontally across the rubber bumper &
spring on the passenger side of the car (where the spring enters the cross
member frame.) Take the jack and raise the spring just enough to relax
the spring on the passenger side lower control arm (The arm should be able
to move about 3/4” or so up & down if the tension is off the spring on
that side. Remove the passenger side lower control from the car at this
point (15mm bolt, 11/16” nut. It is actually an 18mm nut I think but I
didn’t have wrench that size & the 11/16” fit perfectly) Note: The
service manual doesn’t mention taking the lower control arms off but
there is no way to get the spring out with them in place with out the
spring compression tool GM uses. (If you figure out how to do this please
let me know. I spent 3 hours trying to come up with some other solution.)
Lower the jack removing the tension from the spring. Now place the jack
back under the front frame cross member & jack the car up to a minimum of
20” from the ground to the bottom of the cross member. (Don’t forget
about hood clearance & overhead objects if it is raised.) You may need to
place several boards under the jack & several blocks between the jack head
& frame to get the car this high. If you do make sure any boards under
the jack are solid, nailed together & as least 4” wider than the jack on
each side & 12” longer than the jack on each end. The blocks between
the jack & the frame must also be nailed together & should step down to
the jack head if they are of different sizes. The bigger the better so
the load will be spread & also to stabilize the jack head under the frame.
Don’t put several small blocks the size of the head on top of the jack
its dangerous. The best way would to use a big floor jack with a 30” or
so throw however a regular home type jack will work. After the car is up
slide the spring out of the cross member frame from the passenger side.
Next slowly lower the car back down to the jack stands. Do what ever you
need to do & reverse the steps listed above to put the car back together.
Only tighten the lower control arm bolts to 45 lb/ft or so (snug). Drive
the car around the block to seat the bushings on the control arm then pull
the front of the car up on the tire ramps & tighten the control arms bolts
to 96 lb/ft. This prevents the bushings from being put under a torsional
load.
One side note: The spring is difficult to get lined up
left to right when putting the car back together because of the uneven
pressure exerted on the spring as it is worked back up into place one side
at a time. While fairly easy to move with the control arms down any
tension at all on the spring will make it difficult if not imposable to
move. After a lot of though I came up with the following idea. After
replacing the lower control arm I centered the spring in the frame (using
the drain holes in the lower control arms & the spring retainer mounts as
references.) Then I took two large aluminum blocks I had that measured
about 5” wide, 4” tall, & 8” long (any solid material with similar
dimensions should work.) I then took lithium grease and smeared it all
over the floor under the lower control arm ball joints (The concrete in my
garage is epoxyed so it is very slippery). I also put grease on the tops
of the blocks on the end that would be under the control arms. The blocks
were placed under each ball joint & the car was raised so the jack stands
could be lowered (not removed but only dropped about 4”). Then slowly
(like over the next 1/2 hour) I alternated between lowering the car a bit
at a time and tapping the blocks out so the zerk fittings would not press
against the blocks & be torn off of the ball joint. This allowed me to
”raise” both sides of the spring at the together keeping it from
shifting inside of the frame. With the spring compressed I could get the
spring retainers back in place to hold the spring. The control arms slid
on the blocks & the blocks slid on the floor very smoothly with no damage
to the joints, blocks or floor. Except for the mess from the grease it
worked like a charm. If someone comes up with or knows a better way
please let me know.