Body Mounting Hardware
August 28th, 2017, 07:22 PM
#2
Registered User
Join Date: Aug 2017
Posts: 1
OH Ive replaced plenty of them! Back when I knew I was going to restore my 1972 Delta 88 I plowed through salvage yards looking for original pieces that were in good shape. Since then, unless you are in Arizona or Texas, such vehicles no longer exist in salvage yards. I turned instead to full size Cadillac Fleetwoods. Similar size rubber donuts.
Be careful where you jack up the body off the frame. Have the frame supported on jack stands and use large broad blocks of wood to spread out the load on the underside of the body as you lift. Only lift enough to get your hand in and remove the original mount. They can often be stuck after so many years of compression.
You may also find that the thin metal washer or ring on the bottom of the upper mounts are rusted and blistering out of the mount. Remove or scrape it out. It does not affect the performance of the mount. It just aided in locating the mount in the hole at the factory. Just be gentle about lowering the body so that you don't smush them to one side. Do one side of the car at a time. Remove all the bolts on one side and just loosen the ones on the other. That will keep the body aligned.
The lower mounts were common to many GM vehicles and you can scrounge yards for them. Cadillac mounts again will do the job.
Don't over tighten the mounts. Just 25 ft lbs.
You may have to grind the rust off the collars that go inside the upper mounts. They rust pretty bad despite being enclosed in rubber.
If your going to replace them on 71-76 88 and 98's, you'll have to remove the front end sheet metal. Quite a task. You MIGHT be able to disconnect the front fenders where they attach to the radiator support bar but when you jack up the body the paint at the point of attachment to the radiator support will gouge. Be careful and stuff a rag in between the fender and the support.
The mounts on either side of the firewall have two on each side. One is usually thinner than the other. If you get ones from a Cadillac you may have to shim one to mimic the height of the original.
You may find that the rubber donuts themselves are OK and that the reason you are getting a harsh ride is because the inner collars have scaled up rust. Grind that scale off and the mounts may work properly again.
Note, the mounts behind the rear wheel wells on the 88's typically are just round chunks of rubber, as are the ones on top of the frame near the rear springs. Unless all pancaked out, they can easily be reused.
There are aftermarket units available but I've not tried them. They are typically just round donuts of urethane or rubber. Nothing special. The originals had color codes on them delineating their durometer (stiffness or softness) for the particular place they were mounted on the frame. The insides were hollowed out specifically to match the vibrations that they would endure on that part of the body and frame. This was called "tuning". Frankly, I don't think it makes any difference in the ride quality.
Remember to disconnect the transmission shift shaft and the parking brake cable.
If you vehicle is from the northern states with road salt, you may be dismayed to find that the sheet metal pans where the mounts bolt to that are spot welded to the body floor pan are rusted away. In that case, you are in for major, major reconstructive surgery. Nobody makes such sheet metal parts, although there is some full size Chevy sheet metal pans meant for 71- 76 Carpice that might work. Ive not tried that either. But if you find that the pans are rusted away, you may as well scrap the project unless you can put the body on a rotisserie inside a big garage and are handy with a welder. The body mount pans form an integral part of the body/frame structure and once compromised with rust, the vehicle will never ride like new no matter what mounts you use. You should probably shop around the net for an unrusted body and frame onto which to transplant your good parts. That's what I ultimately did and it was worth the lack of headache in trying to restore road salt damage.
Hope all of this helps!
Be careful where you jack up the body off the frame. Have the frame supported on jack stands and use large broad blocks of wood to spread out the load on the underside of the body as you lift. Only lift enough to get your hand in and remove the original mount. They can often be stuck after so many years of compression.
You may also find that the thin metal washer or ring on the bottom of the upper mounts are rusted and blistering out of the mount. Remove or scrape it out. It does not affect the performance of the mount. It just aided in locating the mount in the hole at the factory. Just be gentle about lowering the body so that you don't smush them to one side. Do one side of the car at a time. Remove all the bolts on one side and just loosen the ones on the other. That will keep the body aligned.
The lower mounts were common to many GM vehicles and you can scrounge yards for them. Cadillac mounts again will do the job.
Don't over tighten the mounts. Just 25 ft lbs.
You may have to grind the rust off the collars that go inside the upper mounts. They rust pretty bad despite being enclosed in rubber.
If your going to replace them on 71-76 88 and 98's, you'll have to remove the front end sheet metal. Quite a task. You MIGHT be able to disconnect the front fenders where they attach to the radiator support bar but when you jack up the body the paint at the point of attachment to the radiator support will gouge. Be careful and stuff a rag in between the fender and the support.
The mounts on either side of the firewall have two on each side. One is usually thinner than the other. If you get ones from a Cadillac you may have to shim one to mimic the height of the original.
You may find that the rubber donuts themselves are OK and that the reason you are getting a harsh ride is because the inner collars have scaled up rust. Grind that scale off and the mounts may work properly again.
Note, the mounts behind the rear wheel wells on the 88's typically are just round chunks of rubber, as are the ones on top of the frame near the rear springs. Unless all pancaked out, they can easily be reused.
There are aftermarket units available but I've not tried them. They are typically just round donuts of urethane or rubber. Nothing special. The originals had color codes on them delineating their durometer (stiffness or softness) for the particular place they were mounted on the frame. The insides were hollowed out specifically to match the vibrations that they would endure on that part of the body and frame. This was called "tuning". Frankly, I don't think it makes any difference in the ride quality.
Remember to disconnect the transmission shift shaft and the parking brake cable.
If you vehicle is from the northern states with road salt, you may be dismayed to find that the sheet metal pans where the mounts bolt to that are spot welded to the body floor pan are rusted away. In that case, you are in for major, major reconstructive surgery. Nobody makes such sheet metal parts, although there is some full size Chevy sheet metal pans meant for 71- 76 Carpice that might work. Ive not tried that either. But if you find that the pans are rusted away, you may as well scrap the project unless you can put the body on a rotisserie inside a big garage and are handy with a welder. The body mount pans form an integral part of the body/frame structure and once compromised with rust, the vehicle will never ride like new no matter what mounts you use. You should probably shop around the net for an unrusted body and frame onto which to transplant your good parts. That's what I ultimately did and it was worth the lack of headache in trying to restore road salt damage.
Hope all of this helps!
August 29th, 2017, 07:40 AM
#3
Registered User
Thread Starter
Join Date: Aug 2010
Location: Massachusetts
Posts: 24
Prince,
Thanks for the lengthy reply and all the info!!!!
I am pretty familiar with the mounts, I have taken apart a bunch of this cars. I have been "restoring" a 71 88 rag top for a VERY long time. It is currently a rolling frame, I had to patch some of the body mount locations in the frame. And a couple of the cage nuts need repair. I will need mounts for this one someday.....
My immediate issue is another 71 88 rag top that I picked up a number of years ago. Just did all the suspension and noticed some missing / damaged body mounts, that I want to fix. I am in the Northeast and am aware of the rust issues I will find, but I can fix them, just need suitable mounts.
I have a collection of worn / shattered/ mounts, but nothing usable. What vintage Caddys are you using mounts from?
Thanks again!!!
Thanks for the lengthy reply and all the info!!!!
I am pretty familiar with the mounts, I have taken apart a bunch of this cars. I have been "restoring" a 71 88 rag top for a VERY long time. It is currently a rolling frame, I had to patch some of the body mount locations in the frame. And a couple of the cage nuts need repair. I will need mounts for this one someday.....
My immediate issue is another 71 88 rag top that I picked up a number of years ago. Just did all the suspension and noticed some missing / damaged body mounts, that I want to fix. I am in the Northeast and am aware of the rust issues I will find, but I can fix them, just need suitable mounts.
I have a collection of worn / shattered/ mounts, but nothing usable. What vintage Caddys are you using mounts from?
Thanks again!!!
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