The C3 model of the Chevrolet Corvette spanned from 1968 to 1982. The frame and body mounts of these cars were identical. The eight body mounts are referred to as No. 1 through No. 8. Mounts 1 through 4 are on the driver's side, with 5 through 8 found on the passenger side. The No. 1 and No. 5 mounts are just behind the front wheel, and No. 2 and No. 6 are under the front kick panel. The No. 3 and No. 7 mounts are in front of the rear wheel, and No. 4 and No. 8 are behind the rear wheel. Replacing the body mounts on a C3 Corvette is time consuming and difficult, but can be done with a few garage tools. Use the Corvette assembly manual to study the body mount diagrams and associated assemblies.
Find a level surface and place the car on four jack stands. Remove the eight bolts on the two rear bumper mounts using an open end wrench. Be careful not to knock the shims loose from the frame.
Disconnect the antenna ground strap on the left rear side of the car with an open end wrench.
Remove the No. 1 and No. 5 body mount access covers using a socket or open end wrench. Disconnect the ground strap near the No. 1 mount
Remove the rocker panels. Remove the front grills, lower panel and spoiler using a screwdriver and wrench set.
Remove the screws holding the door sill plates and front kick panels and remove them from the car. This will expose mounts No. 2 and No. 6.
Remove the rear wheels using a lug wrench. Remove the access covers on the front side of the rear wheel well using a socket or open end wrench. This will give you access to the No. 3 and No. 7 body mounts.
Remove the rag joint bolts holding the steering column to the steering box using two open-end wrenches, one to hold the bolt into place while loosening the nut. Disconnect the clutch linkage rod if the car is equipped with a manual transmission. Remove the two bolts that connect the master cylinder to the power brake unit.
Remove the front bumper cover. Look under the car and locate the two front frame extensions. They connect the front portion of the frame horns to the front bumper. Remove the bolts that hold the corner bumper bracket to the frame extensions using an open end wrench. Remove the two bolts that hold the frame extension to the frame and remove them from the car.
Begin on one side of the car and loosen all of the body mount bolts on that side. Spray some penetrating lubricant on the bolts if they are rusty. Do not remove them. Remove the body mount bolts on the opposite side. Remove the bolts holding the body support bracket to the frame, and loosen them on the other side.
Place a 2 by 4 or support block under a jack on the car between the body mounts just under the door. Carefully jack the car up about 3 inches. Make sure there is no resistance or binding present. Install the new bolts and mounts taking care that the shims are not disturbed.
Gently lower the jack, making sure all bolts and shims are properly aligned. Install the nuts but do not fully tighten.
Repeat the process on the other side.
Tighten all body mount bolts securely and evenly. Install the front body support bolts, frame extensions, and bumper supports. Reattach both grounding straps. Reinstall the body mount access panels, rocker panels, and kick panels. Reinstall the front bumper cover, grills, lower panel and lower air spoiler. Reattach clutch rod and reassemble the bolts in the steering rag joint. Reconnect the bolts holding the master brake cylinder to the power brake unit.
