Body Mounts? kit question

donnie_19

Well-known member
Joined
Dec 20, 2012
Messages
305
Location
Troy, MO
Most of my body mounts rubber bushings are crumbling. Currently doing the LS and Vintage Air so the front 2 are easy to get to now. Looking around and the various kits and trying to figure out the differences. Some of them depending on vendor are just the rubber bumpers, bushings, and washers. $60 or so. The other kits are more complete with shims and bolts $160. $100 for bolts and shims seems a little high to me since I can buy grade 8 bolts for $5 a pound. What am I missing?
 
I bought the poly kit from Ecklers, was happy at first but after 6 years and maybe 5000 miles the poly is crumbling, I have a thread with photos here (I'll add a link once I found it)

I'll have to do it again and I am on the fence between Energy Suspension poly (they have a good reputation across numerous online forums, haven't found many complaints about their products)... or aluminum..... aluminum will last quiet a while but rumor is it's a harsher ride....

never been a huge fan of rubber but would prefer that over the cheap China poly ......

bolts and washers are cheap at TractorSupply for example.....
 
Last edited:
Good info. That's what mine look like after 35 years. Would like to replace with something I don't have to deal with again. Only plan on doing the front as I have plenty to do with the LS swap. Thinking of going with rubber. When looking the kits over I don't see paying an extra $75 for bolts, nuts, shims and washers. What am I missing.
 
Last edited:
the Energy Suspension poly kit is $50 at Summit or Jegs.... bolts and washers are a lot cheaper at the local hardware store. Lowes sells fender washers, they even have different thicknesses available. $75 for bolts and washers is a joke..... rippoff.....

I would think that as long as you stay away from the cheap China poly you'll be fine.

I am a little worried that the rubber cushions are just as bad as the poly junk that I bought.... most of this crap is made in some country where labor is cheap, quality doesn't matter and a worker is replaceable.... the big Corvette parts vendors don't give a $hit (just my opinion), they make so much profit with shiny wheels, cupholders and shirts that they could care less about the poly junk that maybe 1 customer a year complains about. *rant over* .... I have hope that Energy Suspension's stuff is better because that's all they sell.... if their poly products get a bad rep they can easily go down..... so I hope their quality is better than the junk I bought ..... wonder if their stuff is still made here in the US....
 
Purchased these Prothane Polyurethane Body Mount Bushing Kit. I can get grade 8 bolts and washers for $4.85 per pound at the farm and home store. They have a great selection of grade 8 course and fine threads.
Hope the bolts in kick panels come out. Can't see how to get to the nut?
 
here's a link to my installation (lots of photos)

http://www.vettemod.com/forum/showthread.php?t=2062&highlight=poly

and here's what the rubbish looked like after a few years (but not many miles)..... UV rays should not be an issue either as these bushings are under the car and also in a dark garage for the most time.....

http://www.vettemod.com/forum/showthread.php?t=7083&highlight=poly+junk
I attempted to remove the bolts for the body mounts today. Got the ones broke loose by the firewall. Next step was the Mount no. 2. Sprayed the cage nut and threads in frame with thread blaster as best I could a few days ago. Tried to unloosen with a 6 point socket and it started to round the head of the bolt. Might be able to use a small pipe wrench on the head , I am open to suggestions.
 

Attachments

  • Corvette 78 Rust Kick Panel.JPG
    Corvette 78 Rust Kick Panel.JPG
    147.1 KB · Views: 13
take a small drill bit, let's say 1/8" and drill thru the washer, the body mount cushion and stop when you "feel" that you're hitting the nut and the cage.... drill at a slight angle towards the bolt..... hope this makes sense, a sketch would probably help ....lol
try to get the penetrating oil to the threads where it's needed, spray it down the hole that you drilled.
don't break the bolt.... you cannot get to that nut without lifting the body....
 
Got 6 of the body mount bolts out today. Need to work on the 2 at the rear tomorrow. Forgot to take a picture tonight but am going to have to redo the rear. Both brackets are shot. Will need to do some fiberglass repair and reinstall the rear body mounts. Where is the cheapest place to buy these brackets? I need both sides.
 

Attachments

  • Corvette 78 Rear Body Mount.jpg
    Corvette 78 Rear Body Mount.jpg
    49.2 KB · Views: 9
the bracket that's welded to the frame ? just cut and re-weld using some steel from the hardware store ..... the other bracket that's fiberglass'd to the body is a tad more difficult to replace.....

best place to buy? probably one of the trusted vendors..... cheapest place??? try google shopping......
 
the bracket that's welded to the frame ? just cut and re-weld using some steel from the hardware store ..... the other bracket that's fiberglass'd to the body is a tad more difficult to replace.....

best place to buy? probably one of the trusted vendors..... cheapest place??? try google shopping......
The bottom bracket looks thats welded on the frame appears to be solid. Its the metal bracket that attaches to the fiberglass that's toast. Will try and remember to get some better pictures today.
Whats the best way to treat the rust in the birdcage?
 

Attachments

  • photo (1).JPG
    photo (1).JPG
    100.8 KB · Views: 16
Ordered from willcoxcorvette.com 1968-1982 Corvette #4 Body Mount Reinforcement. $45 each.
 

Attachments

  • Corvette No4 body reinforcement.JPG
    Corvette No4 body reinforcement.JPG
    45.6 KB · Views: 5
I bought the poly kit from Ecklers, was happy at first but after 6 years and maybe 5000 miles the poly is crumbling, I have a thread with photos here (I'll add a link once I found it)

I'll have to do it again and I am on the fence between Energy Suspension poly (they have a good reputation across numerous online forums, haven't found many complaints about their products)... or aluminum..... aluminum will last quiet a while but rumor is it's a harsher ride....

never been a huge fan of rubber but would prefer that over the cheap China poly .....

I think the challenge with C3 body mounts is that they are pretty soft and, when installed, are smashed down. I guess C3 mounts need to be more compliant than other cars. Either because the frame and/or the body is too bendy. So, poor processing and too much preload on the mounts is what causes these things to split and crack.

I have not done this yet but, 55-7 Chevy body mounts are the traditional cylidrical pucks that all other cars except C3's use. They also have a raised area that engages the hole on the frame mounts perfectly and or about 1/2" thick.

I have some frome Steele Products who have been making rubber parts forever.
 
Denpo have you tried the spray-on method? Can the solution be dilluted?
Thanks in adance,
Scott
No I didn't, did all my work with bath in the product (small delicated parts).
It's a water solution, so can be dilluted (but that won't make it absorb more rust).
It would take a pump, some tubbing, a way to catch dripping liquid, and quiet some Evaporust.
I don't know in the US, but here in Canada it costs an arm by the liter.
Comes in 4 gallon and drums (cheaper) from specialized distributors tho.
The cool thing with it is that it only pick up the rust.
After that spray some phosphoric acid to inihibit what's left, some tough paint over that and you're golden.
 
Ordered from willcoxcorvette.com 1968-1982 Corvette #4 Body Mount Reinforcement. $45 each.

looks good..... what are you going to use to glue it in place? 3M 8115 or 8116 is some awesome stuff.
These are riveted as well, right ? with the rivets and the glue it will never move ever again......
 
Ordered from willcoxcorvette.com 1968-1982 Corvette #4 Body Mount Reinforcement. $45 each.

looks good..... what are you going to use to glue it in place? 3M 8115 or 8116 is some awesome stuff.
These are riveted as well, right ? with the rivets and the glue it will never move ever again......
After I get all the gunk and old parts removed I plan on laying some new glass mat to reinforce the area, but I am open to suggestions.
Will use either Kleanstrip or Rustoleum, they have a rust converter in a spray can to treat the inside cavities.
 

Attachments

  • Corvette 78 Rear 4 body mount top view.JPG
    Corvette 78 Rear 4 body mount top view.JPG
    131.2 KB · Views: 13
Number 4 body mount bolts removed and ready to reconstruct. Number 4 on drivers side needs the fiberglass hub to be rebuilt. It is cracked and separated from the rest of the body. Open to suggestions on best way to fix. The support bracket the is welded to the frame has significant rust damage. Looks like I can add a new plate and repair these mounts. Of all the mounts these were in the worst shape.
Will try to get a better picture of the problem.
 

Attachments

  • Corvette 78 body mount 4 driver side.JPG
    Corvette 78 body mount 4 driver side.JPG
    105.7 KB · Views: 12
Last edited:
on number4: isn't there a metal piece on the inside and outside? once you got these two pieces removed the fiberglass repair shouldn't be all that difficult.

any success on number two ?
 
Back
Top