I've got a 79 and I need to change out all the bodymounts. They are all rusted and the bushings are nearly non-existant. Is there a trick to changing these or are they pretty straight forward. Haynes is next to useless(as usual) on this part of the car. I am planning on using the polyurethane bushing to replace the rubber and I've been told this is a job you will only do once if you use them.
Also I am planning on putting a locker in the rear end and I need an open carrier since my car has a posi. I'm not sure how many vettes came with open differentials so I need something that will fit in the housing and still be useable with the independent rear. I've only worked on solid rears up until now so this is whole new world here. Anyway, any help in these areas would be greatly appreciated.

Daniel

 

I can't help you here, but welcome to the Forum. Someone will help you out for sure.

 

Welcome to the Forum.

You might do a search in the Archive for body mount replacement. There should be several threads.

I used the rubber body mounts as I think the quality of the ride is much softer than the poly mounts. (The early sharks used metal mounts.)

This job can be easy or not so easy. The metal attachment points on the frame for the number 4 body mount (rear) on my car were rusted and the metal was VERY thin. (The rest of the frame is great - no rust.) I also had the number 3 passenger's side mount bolt strip when I was removing it. No problem with the other bolts but this one I had to cut out.

That lead to doing a body lift so that I could remove the remnants of the old bolt. In retrospect it would have been better to lift the body in the first place as working on the engine, trans, trailing arms, exhaust, etc, etc, ... is much easier.

I had to weld new #4 frame mounts to the car. Just don't be surprise if you have similar problems - I hope not - just don't be surprised.

There is may also be some useful information at:

http://www.corvettefaq.com/


[Modified by mapman, 1:27 AM 12/27/2003]

 

Just how bad is the rust? I did mine this last summer so you can see what I had to do on my web page.
Welcome to the forum and don't be afraid to ask questions.

 

i think i am going to be doing this soon as well...
i, for one am not crazy about the idea of having to lift the whole body with a sling as you would for a body off resto... :rolleyes:

it seems as tho i remember reading somewhere about this where they talked about using 6 small bottle jacks, strategicly placed with 2x6 blocks of wood at the tops of the jacks...

as i recall...the body only has to be raised about an inch or so to replace the mounts/bolts...

anybody know more about this method or has done it this way?

 

Signguy, the jack method should work just fine, but the scope of the entire project will depend on many variables as Redwing was hinting at.

1. What is the condition of the rocker channels? (this is probably the biggest problem area)

2. How good are the (2) rear mounts? Often they are almost gone and will need to be replaced

3. Bolts broken off in the frame will need to be drilled out and re-tapped, an awful (if not impossible) job with the body in place and only up a few inches.

4. What is the condition of the frame itself? Many rust out in the kickups or above those corner braces just in front of the kickups.

My own recommendations on this are start soaking everything with a very good penetrating oil a few days before you want to start, maybe you will get lucky, then take it a step at a time. Be sure to provide for some support under the nose of the body if you end up removing it. Leaving the radiator support in place will help provide a spot for this. If the rocker channels are rusted out, use a sling to go all the way under the body, not the "lift kits" with hooks that lift the body by the rocker channels, severe damage can result.

 

the underneath of my car is very good condition rustwise as you can partialy see in this pic...

some of the mounts are better than others...here is the worst one...
the drivers side, "kick panel" position...

heres the pass side...

and the drivers side rear...both of these are about the same cond...

the two forward and two rears are in very good shape, rustwise...

 

Signguy, your mounts look really good compared to most for this age of a car. You probably won't have too much problem changing yours. Looks like you can even get a wrench or socket on the mount bolts! many times they are so rusted a smaller socket has to be hammered on. :cheers:

 

I did a write-up of what I did on my 71. Take a look in the tech article section of the forum. I had to lift the body about 6" and used 3 floor jacks.

 

Thanks for the info. Looks like I have quite a job on my hands.

The mount all the way in the back the #4 I think, is completely gone. It's just a piece of rubber sandwiched between the frame and the body and maybe a bolt. The fiberglass has cracked and the frame around that area is starting to rust since the rest of the mount fell off. But I'm in no hurry as this car is going to be sitting for a long time.

I currently have the entire rear suspension apart so that I can clean the underside of the body and as much of the frame as I can get to. There is also the matter of the crossmember in the back. It has a bushings on both ends too.

Ahhhh rounded off bolts and rust....I love working on cars

 

I replaced the body mounts in my 81 this past spring. It went real easy. If you want me to give you a step by step just let me know and I will post it here on the forum for you. :thumbs:

 

i for one would really like that...
which method you went with etc...

 

Here's a link to the write-up I did for my 71. Most of the steps apply to yours as well.

https://www.corvetteforum.com/techti...=210&TopicID=3

 

This is long, but here goes. The only things I had to buy were the body mount kit, came with all new bolts and shims, cost $151.95 at local corvette shop. I bought 2 hydraulic jacks at Advance Auto Parts $18.99 each and one sheet of 3/4 inch plywood. I already had one jack of my own.
The MOST IMPORTANT part is to soak all the body mount bolts real good for a few days before doing the procedure. Hopefully this will prevent any of them from breaking.
Just in case someone does not know where they are located: 1- is just behind the rear wheel. Remove wheel and look to your right and up jut a little and you will see the body mount. 2- just in front of the rear wheel. With rear wheel removed look to your left and you will see a small rectangular plate. Plate is held in place with 4 phillips screws. Remove screws and plate, look in hole and you will see body mount. 3- inside car remove small kick plate next to where your left foot would be and down in there is the next body mount. 4- The last mount, remove front wheel and look to your right you will see mount,now on my 81 I had to remove the side grille to get the top of the bolt.
Now the procedure... The best way to do this is to remove your gas tank. When I took mine out I found all the lines rotted and the tank itself starting to rot. its not hard to remove the tank just takes a little more time, but is well worth it. Now crawl under the car in the rear and you will see a big flat shelf above where the gas tank was. Take a measurement of this flat area and cut a piece of 3/4 inch plywood to fit in there. Now, go to the middle of the car and you will find another flat area. Measure and cut another piece of plywood to fit here. Finally crawl under car in front area just before the firewall starts to go up and you will find a small flat area, measure flat area and cut another piece of 3/4 inch plywood to fit there. Now, go to the rear again and put plywood that was cut for there in place and put jack under plywood, do the same for the middle and front areas.
*Only do one side of the car at a time.
Now befoer you go any further you must remove all body mount bolts. The first three bolts are bolted into the frame, but the last bolt, the one behind the rear wheel is incapsulated in a steel cage. The bolt goes through the body mount throught the frame bracket and into the car. Inside the car the bolt has a big nut on it. the nut is held in place by a steel square piece. This steel square piece is tack welded to something and that is what stops the nut from turning. Well, both of my welds broke. this just lets the nut turn and turn. No big deal, go inside the car and remove the rear corner panels, they are held in place by 3 or 4 phillips screws. When you remove this piece you can reach inside and feel the nut. I put a pair of vise grips on the nut and had my wife turn the rachet from below.
OK, now back to the jacks. Go to the rear jack and give it one pump up, go to the middel jack and give it one pump up and finally the front jack and give it one pump up. Keep doing this until you can remove the old body mounts. I only has to raise my vette about 3/4 of an inch to get the old ones out and the new ones in. You will have to play with each one a little to get it out, but its not hard at all. The whole job took me about 5 hours all by myself, except the one time I had my wife come out to turn the rachet.
When you finish with one side do the same thing to the other side.
* Make sure that when you remove the old body mounts you count the number of shims you remove so you can put back the same amount. The whole job came out great. I had no problems at all everything lined up great and the car was not squeaky anymore.
I only did it myself because I took it to a local Chevy dealer and they told me it would be somewhere between $800.00-1100.00 to do this job. I said no way. It cost me &151.99 for the body mount kit $18.99 for each jack(2) and $22.00 to have a piece of 3/4 inch plywood delivered. Plus I kept my gas tank out for about a week and replaced all the gas lines and sanded the outside of the tank and coatede it with sealer and then with undercoating. It also came out great and look like new.
Now here is my phone number just in case someone cannot understand all my babble. (845) 883-5308. I hope I have helped someone and sorry this is so long. Good luck.
Richie Cooper :thumbs:

 

thanx a ton Markus!
very informative...i, for one, appreciate it very much!

 

Marcus, good write up. Did the rubber make the ride quieter on your car? This would make for a nicer ride in mine too.

 

What do you do after this with three floor jacks? Can floor jacks be rented?

 

Buy one more for future use so you can put the whole car on jack stands for more fun :party:

 

My bad; it's hydraulic jacks not floor jacks. :bb

 

Very helpful. Thanks much.

I have access to overhead cranes where my vette is. Would buying one of those body slings be an easier way to go about this? I know the hook ones are not good for the body but they have the ones that go completely under the body and up the other side. Just curious.


Thanks again