Question for those that have done body mount replacements... specifically those that do so without doing a "body off".... How exactly did you raise the vehicle and how high did you have to raise it?

I'm assuming I can jack the vehicle up with just standard floor jacks... The questions I have are, where and how to place the jacks. I figure I can use some 2X4s (to distribute weight) and jack up either one side (or end) of the car, replace the mounts, and then do the other side (end). Is this feasible? Where exactly do you place the jacks and raise the body from? I'd rather not cave in any portion of the underside...

The #1 and #4 mounts on each side look relatively straightforward... The #2 and #3 look a bit tougher.. I'm wonder how high I'm going to have to raise the body to get to those areas.

Thanks for all your info. If you have pics, that'd be even better!

 

Read this....posted by another Forum member. It gives an insight into what to expect.
The rubber body mounts found on 73-82 Corvettes vastly improved noise and ride over the solid aluminum mounts used on the 68-72 models. It is possible to retrofit the later rubber mounts on 68-72 and reap the benefits of a better ride, less road noise and less risk of fiberglass stress cracks. I recommend buying a body mount kit as it also comes with all new bolts, washers, nuts and shims. These kits can be had for about $150. 1. start by placing the rear of the car on jackstands (rear wheels off the ground) and remove the spare tire carrier. 2. You now have easy access to the rear bumper brackets. There 2 in the center that go to the license plate area of the body, 2 that go to the innermost bumper mounts, and 2 that go to the outer bumper mounts. The rear section of the body is very strong and contrary to the front it does not have to be supported during the lift. 3. Disconnect the antenna grounding strap. 4. Disconnect battery cable where it mounts to the frame. 5. Loosen parking brake adjustment as much as it will go. The adjustment is in the transmission tunnel, before the cable splits off to the wheels. You do not have to completely disconnect the cable. 6. Now for the front. Start by removing the front grills. 7. Remove the one bolt holding the corner bumper bracket to the frame extension. The frame extension is the large piece of flat steel that goes from the front of the frame horns to the bumpers. There's one on each side. 8. Remove 2 bolts on each side holding the frame extension to the frame. Remove frame extensions. 9. IMPORTANT! The next step will disconnect the whole front of the body from the frame. YOU HAVE TO SUPPORT THE FRONT OF THE BODY AT THIS POINT. The weight of the front is enough to collapse the body if you don't!!! 10. Place a floor jack under the center of the front body transverse beam. This is the steel piece just infront of the radiator. 11. Remove 4 bolts (2 each side) holding the body support to the frame. 2 of these bolts were hidden by the frame extension bracket removed in step 8. The other 2 are just rearward from the bolts removed in step 8. 12. Now it is time for the bodymounts. There are a total of 8 mounts. They are referred to as #1-#4 (left and right). #1 is behind the side gills, infront of the firewall. 70-72 owners have it made as the gills remove for easy access. 13. #2 is behind the kickpanels. Remove the sillplates and then the kickpanels. The bolt is now accessible. 14. #3 is behind the door. Remove the rear wheels and then the access plate on the front of the rear wheel well. The bolt is now accessible. 15. #4 is behind the rear wheel and visible after the wheels have been removed. 16. Remove 2 bolts to loosen the master cylinder. Tie the mastercylinder to the alternator so that it clears. You do not have to disconnect the brakelines. 17. Remove the bolts holding the steering column rag-joint together. Don't forget the safety studs. 18. Remove the rocker panels. 19. The body is now separated from the frame 9atleast as much as we need to lift it the required 4"). 20. Place 2 more floor jacks, one on each side, approximately 2/3 back under the doors. Carefully test the rigidness of the birdcage rail by lifting slowly. On mine I had problems with the rail bending, so I had to move the jack back and forth until I found a rigid enough section. 21. SLOWLY lift on all three jacks. As you lift, look in the engine compartment, under the car, etc to make sure everything is moving freely. 22. You will have to lift until you can just see the top of the frame under the doors. 23. Now you can remove all the old mounts. Note any shims that are found. Be aware that shims can stick to the body. They have to be removed as the new mount won't fit with a shim in the way. 24. Mount the new rubber mounts according to instructions. They do not all go in the same way. If shims were used on the old mounts, you can tape the shims to the new rubber mount. Use masking tape. This, by the way, is how the factory did it for ease of installation. 25. All mounts should slide through the holes in the body. If they don't, you may have misaligned panels. On mine, all fit except #3. I had to dremel the holes until the mounts installed properly. 26. Lower body down. 27. Re-attach the front end first, using the highest possible attachment. This is done by lowering the front until the bolt holes line up, install bolts (but do not tighten), lift front as high as it will go and then tighten bolts. 28. re-install all items removed in the earlier step, except the steering column rag-joint. 29. The column will not line up as the body now sits ~3/8" higher than with the solid mounts. Loosen the column where it attaches to the firewall, and also the upper bolts. 30. Push the column down in the engine compartment until it lines up. tighten mounts and re-install rag-joint bolts. 31. Enjoy the new ride!!!
Hope this helps
Eddie

 

Thanks. I guess I'm still having trouble visualizing.

Are the jacks placed actually under the floorpan, near the frame... and hence you're lifting by the floor pan? I assume so because I'm not sure what else you can lift by.

 

here are some links to related threads, this should answer most of your questions:

http://forums.corvetteforum.com/showthread.php?t=976790


http://forums.corvetteforum.com/showthread.php?t=972613


http://forums.corvetteforum.com/showthread.php?t=947997


here's a PDF file with tons of photos that is very helpful:

http://NHvette.com/ftp/Body_mounts_small_file.pdf

 

Thanks a ton... that was really the info I was looking for... I had even posted on that first thread, but was unable to locate it again (and hence, the file). My specifics are answered.

 

RB79... after reading the threads... I did have one more question...

You posted this:

How exactly did you verify the were all equally loaded? When you say none of "them" was moveable, what specifically are you referring to?

Sorry if it's a dumb question....

 

So for those that have done this, how long did it take and was it worth the effort?

 

After all eight mounts were replaced and the bolts were not tightened I just tried to move each mount... I think I had seven of the eight tight (couldn't turn them by hand) and the #3 on the passenger side needed some more shimming...

The poly mount kits come with 16 shims, all the same thickness... the fender washers from Lowe's fit perfectly and are available in several thicknesses (all thinner than the ones supplied with the kit)...

It took me almost a week to do it - I only worked on it 2-3 hrs a day (after work), my #3 bolt wouldn't come out and I had some welding to do on #4....

It was well worth the effort !!

 

Thanks again RB79. The upper and lower cushions basically fit together like a couple puzzle pieces I guess... so when you install them (specifically the #2 or #3 mounts) you can attempt twist the upper cushion (as you can't really twist the lower one) and if it moves, that would mean you have space between the lower cushion and the cage... in which case you'd need to shim.

Got it.

For me, the process should be much easier. The interior is gutted so I have a skeleton of a body. Additionally, all the old mounts and bolts are already removed. It's just a bare body sitting directly on the frame with no mounts.... so all I have to do is lift... and insert the new mounts.

 

I think this picture is a good example:


After you have all eight mounts installed and the body is lowered onto the mounts, then you need to check those poly (or rubber) pieces that are between body and frame. Only 8 of the 16 pieces are between body and frame.

On the photo you can see that in this case (driver side #4) it's the upper one)... you can also see a thin fender washer added to the upper mount/shim

 

That part I get... but on mounts #2 and 3.... you can't see the portion of the mount between the body and the frame... So visually, you have no idea whether or not it should be shimmed. What about those?

Heh... sorry... I'm probably sounding awfully dense.... Just trying to make sure I understand exactly how you knew when/what to shim.

 

No, you cannot see #2 or #3 - you'll have to get your hand in there somehow.... I decided to cut the fiberglass at the #3 mounts because I had to re-weld the nut to the frame anyway... see photo:





It is not visible after glueing it back in place: