1957 Corvette RestoMod Story – Page 6
Replace C4 Front Bushings & Ball Joints
The front bushing and ball joint upgrade continues. First, we remove all bushings from the control arms, both upper and lower arms. I replaced these worn rubber bushings with new polyurethane red ones from Energy Suspension. Rubber is nice, but PU is better.
Polyurethane produces a stiffer ride because of their density and strength. And they last much longer. Rubber bushings are susceptible to road and weather damage. To see this, look at your vehicle’s bushings. If they are cracked or breaking apart, time to replace them.
Chapter 5 of my book goes into detail on how I removed and replaced the bushings and ball joints in my Grand Sport front-end.
Below, the ball joint in the upper arm is riveted from the factory. You can see I drilled a pilot hole to remove all rivets and release the ball joint.
Above: this ball joint is toast. A grinder can also be used to grind off the heads of the rivets, then use a punch to push them out.
New ball joints from Rock Auto are installed using the nuts and bolts in the kit. The dust boot is from Energy Suspension, and I used it instead of the supplied black one.
The upper control arm is smaller than the lower control arm. This contributes to the incredible handling of the C4 suspension system. Many C4’s have been used as competition cars in autocross due to their excellent cornering characteristics.
Combined with the high-torque capability of the LT4 engine, the C4 platform was a tough car to beat. Autocross is like a mini version of road racing. Cones are used in a “parking lot” setup of the course and tight turns are the norm. Next, I tackled the removal of bushings from the upper control arm.
Shown left is an upper control arm. Bushings must be removed by pushing the pivot bar and bushings through both eyelets. A lot of force is needed to do this. If the “Y” arms are not secured somehow, they will bend, possibly beyond repair.
So I came up with a jig on my well-worn B&D Workmate. The jig secured the arm and allowed the necessary force to push out the bushings – a lot of force.
If you want to know how I built my upper control arm jig, you’ll have to buy Chapter 5 of my book – sorry, I can’t give away all of my secrets here. And I also show you how to do this with a shop press.
I tried to secure the upper ends of the “Y” of the control arm, but this was insufficient in preventing possible damage. The “Y” arms started to bend too much, so I backed off and thought about it. My solution was easily accomplished using materials around my garage – stuff that I’m sure you have as well!