Been lurking here for a while, trying to learn as much as possible before buying my first Corvette. I've looked at 6-8 cars, mostly 78-82's. I've been checking the usual items (frame rust, body panel alignment, etc), but almost without exception, the body mounts are shot. Especially the ones behind the rear wheels. Is this a DIY job for the average joe? I have a 78SA I'm looking at that looks really good except for the mounts. Thanks for your input.

 

I'm wondering if I can put in the poly mounts with the body still on the car. I am thinking that I should be able to loosen all the mount bolts, lift up each end of the car-one at a time- and slide in new mounts. Once they are all in,I can tighten all the bolts and be done. My frame is in great shape, but there is some surface rust. I am POR-15'ing the entire frame and want the mounts to look new too. Anyone have input?

 

Not a big job to change the #4 mounts. If you're really lucky the bolts will come loose without a fuss. If you're not so lucky you might have to crawl in back and lift the carpet to soak the heck out of the nuts with penetrating oil to break the rust loose. At the worst, you might have to have a friend clamp on to the nut with vice grips while you back the bolt out. Even if you have to cut the bolt head off and remove the nut and cage, just have a friend hold the nut in place when replacing with a new bolt. You can slide the new rubber biscuit into place while the bolt is out.

There is a sheet metal reinforcement at that mount that tends to rust out too. You may have to push the body up a bit away from the frame to get the old one out and slide the new one in place. You'll probably have to loosen the rear bumper to do this but a Corvette body is very flexible when it's loose from the frame. You can pop rivet it in place if you're not fussy about originality. Use pop riviets with big heads to spread the load over the fiberglass (my hardware store guy calls them "snowmobile rivets" because they're used to fasten brackets to the fiberglass cowls) or at least use washers. The original rivets were solid aluminum that were staked in place with a rivet setting tool which is the route that I went.

Another thing to think about is if the #4 mount looks bad what do the others look like? The #2 and #3 mounts are harder to access and may involve lifting the body off the frame a bit to access them. That's considerably more involved!

You may want to have someone that's knowledgable about Corvettes take a look with you and get their opinion first hand on how involved the job will be. A job like this is often like an iceberg; 9/10 ths of it are hidden.

At any rate, welcome to the Forum. This place is full of knowledgable people that are willing to help out. :cheers:

Good luck on your search.

 

Eric pretty well summed it up! :yesnod:

 

Thanks for the feedback. I assumed if #4 was shot, some of the others would be also. I guess the real question would be if bad mounts would keep you from buying an otherwise decent car. I'm trying to get a feel for the PITA factor of doing new mounts. :cheers:

 

Not necessarily. #4 in my car was virtually nonexistant. I mean they came out in small pieces, looking VERY bad. It's a rough spot for a metal piece, and putting aluminum rivets in contact with a steel reinforcement isn't the best engineering idea, either.

Instead of just lifting the rear, I lifted the whole body up about a foot. The #2 ans #3 mounts were ok, except the bolt had rusted to the nut, and the cage was weak enough that the excessive torque I applied ended up spinning the nut in the cage. So I had to us a dremel and lots of time to lop off those bolt heads and then replace the cage nuts on the frame. But they were by no means disintegrating or anything. They would have been fine for another 15 years had I not messed with them.