How do you know if your Corvette’s 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 your Corvette’s front suspension move forward or back, replacement is the answer. Sometimes your Corvette 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 Corvette’s 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 corvette had a worn out upper control arm bushing so we contacted Zip Corvette Parts, 8067 Fast Lane, Mechanicsville, VA 23111, (800) 962-9632, and they were able to supply all of the needed Corvette 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 Corvette shop manual along with this article, it is fairly straight forward. Now with this in mind, let’s get started.
Click on the images for expanded views – it’s much easier on the eyes.
01:These are the items we received from Zip Products. 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.
02: Start by jacking up your Corvette and placing the jack stands under the outer area of the lower control arms. You want the weight of your Corvette supported on the lower control arms.
03: Remove your Corvette’s 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.
04: Keep the drum and spindle assembly from hanging by using a bungee strap. Hook it to your Corvette’s frame or drag link.
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.
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.
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.
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.
09: Now remove the cap screws, lock washers, and collars from both ends of the control arm shaft.
10: Install a 3/8-24×2¼” 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.
11: Thoroughly clean the control arm and refinish it with Eastwood’s Underhood Black. This will give it a new look.
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.
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.
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.
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 Corvette for National Show Competition, you cannot bolt the ball joints back into place. You must have them riveted.
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.
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.
18: You can now lube the ball joint. Re-install the tire and wheel and lower the car to the ground.
19: After your Corvette 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.
20: For reference, here is what an upper control arm bushing looks like when the rubber has disintegrated.
21:This is the way it should look with the rubber compressed between the collar and the bushing.
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.
Corvette UCA Bushing / Ball Joint:
How To Replace Corvette Upper Control Arm Bushings And Ball Joints
Source: Zip Corvette Parts
8067 Fast Lane | Mechanicsville, VA 23111 | (800) 962-9632
Corvette Parts List Related to Article:
- Ball Joint To Control Arm – 25 Ft. lbs
- Ball Joint To Spindle – 42-47 Ft. lbs.
- Cross Shaft To Crossmember – 65-75 Ft. lbs
- Cross Shaft End Cap Screws – 35-40 Ft. lbs