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How do you know if your upper
control arm bushings are going bad? One
of the easiest ways is to physically inspect them. If the rubber part of the bushing is
deteriorated, cracked or even missing, it is time to replace them. If every time you pull forward or back up you
hear a clunking sound or actually feel the car’s front suspension move forward
or back, replacement is the answer.
Sometimes the car will actually pull to the side that needs replaced
every time you step on the brakes, acting just like a brake that is pulling.
If
your upper ball joint is bad, it will mimic some of the same conditions as the
upper bushings. Since these are both
very important front suspension parts, any problem should be corrected
immediately.
Our
Project 64 had a worn out upper control arm bushing so we contacted Zip
Products, Inc., 8067 Fast Lane, Mechanicsville, VA 23111, (800) 962-9632, and they were able to supply all of the needed parts.
The
repair is not very hard but you will need access to a hydraulic press,
hydraulic jack and jack stands. The
whole replacement process can be done in one afternoon and as long as you
follow your shop manual along with this article, it is fairly straight
forward. Now with this in mind, let’s
get started.
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01: These are the items we received from Zip. Upper ball joints, control arm shims, control
arm alignment nuts, control arm alignment studs and upper control arm shaft kit
which includes the shaft, bushings, retainers and nuts. You will also need a ball joint separator,
jack stands, hydraulic jack, hydraulic press, hand tools, torque wrench and a
shop manual for your year Corvette. |
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02: Start by jacking up the car and placing the jack
stands under the outer area of the lower control arms. You want the weight of the vehicle supported
on the lower control arms.
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03: Remove the tire and wheel. Also remove the cotter key and nut from the
upper ball joint. Now take a ball joint separator
tool and separate the ball joint from the spindle. A few solid hits of a hammer should do it. |
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04: Keep the drum and spindle assembly from hanging by
using a bungee strap. Hook it to the
frame or drag link.
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05: Loosen the 2 nuts holding the upper control arm shaft
in place and carefully remove the alignment shims from the front and back. Do not mix up the shims. After you have removed the nuts and shims,
keeping the shims in order, then remove the control arm.
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06: It is very important that you make a note of the
number of shims in both the front and back of the control arm shaft. These are used to shim out the front end for
proper alignment. Each shim is a
particular width so they must be kept in order and replaced in the same
location. I always tape the shims
together and name their location. |
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07: Place the upper control arm in a vise and remove the
upper ball joint. If the ball joint is
the original one, it will be riveted in place.
You will have to remove the rivets.
This can be done by either drilling, using a die grinder, or using a
chisel. The choice is up to you. I usually use a die grinder to grind off the
head of the rivet. Then use a punch to
drive the remaining stud out. |
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08: The new ball joint is held in place by bolts. These new bolts are larger than the rivet
holes so you will have to enlarge them.
Use a 21/64 drill bit to drill out the rivet holes to accept the new
bolts. |
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09: Now remove the cap screws, lock washers, and collars
from both ends of the control arm shaft. |
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10: Install a 3/8-24x2¼” cap screw in one end of the
shaft. Place the control arm in a press
and support one bushing end of the control arm shaft with a 1 11/16”
socket. Now press out the bushing into
the socket. Invert the control arm and
repeat the process on the other bushing.
Both of the old bushings should now be out of the control arm.
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11: Thoroughly clean the control arm and refinish it with
Eastwood’s Underhood Black. This will
give it a new look. |
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12: Don’t laugh.
This is the best way to store new bushings until you are ready to use
them. Bushings that are kept in a
freezer will contract and will install much easier. Once they warm up to room temperature, they
will expand and be snug and secure. |
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13. Place the control arm in the
press and install one bushing. Use a
1 5/16” socket to press the
bushing into place. You will also have
to support the inside of the control arm.
You can see it here around the shaft.
The easiest way to make this support is to use a 1 3/4” or 2” pipe
(fence post will work). Cut it to fit
between the inside flange of the control arm.
Now cut approximately a 1” slot into the pipe. This will allow it to fit around the shaft
and the bushings. Now you have a special
control arm support. After you have
installed the first bushing, install the cross shaft in the arm. Invert the arm in the press and then press in
the second bushing. Make sure that the
cross shaft can be turned by hand. It
should not bind after it is installed.
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14: The collar, lock washers and cap screws can now be
installed. Snug them into place but do
not tighten them. This will be done
later. |
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15: Next you can install the new ball joint. Fit it into the control arm, install the
bolts and nuts and torque them to 25 ft. lbs.
NOTE: If you are
rebuilding your car for National Show Competition, you cannot bolt the ball
joints back into place. You must have
them riveted. |
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16: Re-install the control arm back onto the
crossmember. Remember to have the
mounting studs in position. Install the
nuts onto the retaining studs. Then
re-install the alignment shims making sure you replace them in their original
position. When the shaft is installed,
torque the cross shaft nuts to 65 to 75 ft. lbs. |
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17: Now install the rubber boot on the upper ball
joint. Place the ball joint into the
spindle and install the nut. Torque the
ball joint stud to 42 to 47 ft. lbs.
Align the hole in the stud and install the cotter key. |
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18: You can now lube the ball joint. Re-install the tire and wheel and lower the
car to the ground. |
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19: After the car is on the ground, bounce the front end
of the vehicle. This will center the
upper control arm bushings. Tighten the
collar bolts to 35 to 40 ft. lbs. |
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20: For reference, here is what an upper control arm
bushing looks like when the rubber has disintegrated. |
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21: This is the way it should look with the rubber
compressed between the collar and the bushing. |
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22: Here is another helpful hint: Always replace the cross shaft alignment
bolts whenever you remove the cross shaft.
These bolts have a serrated area below the head and when they are
removed, they lose some of the serration.
When this is removed, they will lose some of the grip and will spin in
the cross shaft when they are tightened. |
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UCA BUSHING/BALL JOINT:
UPPER CONTROL ARM BUSHINGS AND BALL JOINT REPLACEMENT
SOURCE:
Zip Products, Inc.
8067 Fast Lane
Mechanicsville, VA 23111
(800) 962-9632
PARTS LIST:
TORQUE SPECIFICATIONS:
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Ball Joint To Control Arm
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25 Ft. lbs
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Ball Joint To Spindle
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42-47 Ft. lbs.
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Cross Shaft To Crossmember
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65-75 Ft. lbs
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Cross Shaft End Cap Screws
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35-40 Ft. lbs
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The Author would like to thank Scott Coral of Greg Donahue Collector Car Restorations, Inc. for his
assistance with this article.
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