by John Pfanstiehl
This is the third in a series of three tech articles covering replacement of body mounts on 1963-1982 Corvettes. Shown here are the details of replacing the body mounts without removing the body, once the body mount bolts have been removed.
The first tech article, 1963-1982 Corvette Body Mount Replacement Part 1, provides tips and solutions on removing the bolts from the #1 and #4 body mounts. The second tech article, 1963-1982 Corvette Body Mount Replacement Part 2, covers the particular problems and solutions for removing the bolts from the two central mounts, #3 and #4. These two tech articles provide information on solving the problems caused by rusted fasteners that factory manuals don’t cover.
After the eight body mount bolts are loosened and removed, the body can be lifted up from the frame about 1-½- inch to enable the new body mounts to be installed. The first order of business is disconnecting the several items that connect the body to the frame. These items, along with several other parts, also would be disconnected to remove the body completely off the frame.
Next shown is how to install the body mounts, followed by checking and adjusting door alignment. The last steps are installing the bumpers, bumper brackets, supports and reconnecting the steering column, ground straps and other parts. With this series of three tech articles, Zip Corvette provides helpful information to its customers that is found nowhere else.
01: Inspect or photograph the gaps on the front and rear of each door while the car is on the ground. If the gaps are OK and the doors open and close without binding, then the goal is to replicate the gaps when the body mounts and shims are installed.
02: Disconnect the steering column from the steering box at the rag joint. Remove the two nuts and lock washers that attach the rag joint to the coupling on the steering box. Then remove the coupling bolt with a 7/16-inch 12-sided socket in order to slide the coupling rearward on the steering column shaft. Tip: tap a screwdriver into the slot on the coupling to expand it and make it easier to slide on the shaft. If the old rag joint shows wear or deterioration, Zip Corvette offers a number of new 1963-1982 Steering Column Rag Joints.
03: The master cylinder may need to be unbolted. In this case, it was not necessary to unbolt it because its brake lines had sufficient bends and length to allow the body to be raised an inch or two. However the clutch rod clip was removed to disconnect it from the bell crank.
04: Note the alignment of chrome bumpers and note the location of any shims that were used between the bumpers and the body.
05: Remove or at least loosen the rear bumper brackets to prevent them from interfering when the body is raised. Likewise on 1975-1982 Corvettes, unbolt any supports that might interfere when the rear bumper cover is lifted up along with the body.
06: Remove bolts that attach the front bumper assembly to the frame. On chrome bumper cars, remove the bumpers and remove or loosen their support brackets.
07: Disconnect one end of any ground straps that would prevent the body from being raised 1½ inches from the frame. Also remove the rocker panel molding. The 1970-1977 Corvette Rocker Molding Install tech article provides more information on that.
08: Remove the old #2 body mount bolts and the other old body mount bolts from both sides. Jack up the car and securely support the frame on jack stands.
09: Place a 2×4 against the body flange. Use a scissors jack to slowly raise the body from the frame. A scissors jack is more stable than a floor jack with wheels. Raise one side of the body at a time, replace those mounts and lower the body back down before raising the other side.
10: A ¼-inch to 3/8-inch thick metal plate can also be used to raise the body. The plate slides up between the flange and the frame and has no risk of slipping off the body flange. It is also a better means to raise the body if the flange is weak or bends.
11: A jack can be used to help support the front end when the body is raised from the frame. That can reduce stress on the body from the heavy front assemblies hanging unsupported.
12: It’s easy to remove the rear (#4) or front (#1) body mounts when the body is raised a little off the frame. After these mounts are removed, temporarily replace them with a solid block for safety while replacing the #2 and #3 mounts.
13: If any newly exposed areas on the body supports or frame are rusted, apply a rust preventative coating. If the frame bracket is too severely damaged, Zip Corvette offers new 1968-1982 #4 Body Mount Frame Brackets.
14: If rust destroyed the cage and nut inside the body on the rear mount and it’s too difficult to place a nut inside the body cavity, the new bolt can be dropped down through the body. Tip: insert a strong magnet up through the body to grab the tip of the bolt and guided it down through the hole.
15: The new body mount is about 1½-inch tall so the body must be lifted at least that far off the frame. However, the old mount held the body about ½-inch off the frame. Therefore, the body only needs to be further raised a bit over an inch. Tip: the thin rubber flange can be trimmed to make it easier in tight quarters to push the mount through the hole in the frame.
16: Pry the two center body mounts (#2 & #3) out from the body. Note the location and number of any shims at all the body mount locations.
17: After the front body mount is removed, the #2 mount can be slid forward for removal. Install the new #2 body mount via the same route before installing the front mount. For safety, make sure to use an extra jack stand or blocks to hold the body up in case the jack slips.
18: When the new body mounts are installed, tighten the front two mounts (#1 & #2).
19: Check the door gaps to make sure they’re satisfactory. If they are OK, tighten the two rearmost mounts (#3 & #4).
20: The rear body mount is visible inside the wheel well. If the rear nut cage was destroyed, the bolt can be installed down through the body like this. Tip: If it’s desired to look more like stock, saw the bolt off at the lower side of the nut and paint the nut black.
21: If the gap is too tight at the door’s upper rear, increase the number of shims on #3 or remove shims from #4. If the door gap is too wide here, increase the number of shims on #4 or remove shims from #3.
22: When the car is back on the ground, check the opening and closing of the doors. On this convertible, it was necessary to adjust the Door Alignment Pin Receiver. The 1970-1975 Corvette Convertible Door Alignment Fix tech article provides more information on that.
23: Tip: install a bolt through the body into the bumper bracket to hold it in place while the brackets are snugged up. It’s helpful to have the brackets in place and have all the bolt threads clean before reinstalling the bumpers.
24: Tip: apply electrical tape to the sharp bumper edges to reduce the chance of scratching or chipping paint when the bumpers are held up to the body for installation. A helper is useful for this step. Reconnect the rag joint and other items to complete the replacement of the body mounts.
1963-1982 Corvette Body Mount Replacement Part 3
Source: Zip Corvette Parts
8067 Fast Lane | Mechanicsville, VA 23111 | (800) 962-9632
Corvette Parts List Related to Article:
- 1973-1982 Body Mount Kit with Rubber Bushings
- 1973-1982 Body Mount Kit with Polyurethane Bushings
- 1973-1982 Polyurethane Body Mount Cushions
- 1973-1982 Upper & Lower Body Mount Cushion
- 1973-1982 Body Mount Bolt Kit
- 1968-1982 #4 Body Mount Frame Bracket
- 1968-1974E #2 & #3 Body Mount Bracket
- 1974L-1982 #2 & #3 Body Mount Bracket
- 1963-1982 Body Mount Metal Shim
- 1963-1982 Steering Column Rag Joints