Body mount #4 Question

[Dan B.]

Can someone please explain what the bolt going through the nut pictured above on the # 4 mount drivers side attaches to. 64 Coupe. I currently have the body raised to repair some items and noticed there is no bolt in this location on mine, but the hole goes through to the inside. Thanks.

[Mark M.]

Re: Body mount #4 Question

That bolt goes through the rear deck hinge bracket of a convertible. Coupe has a different body mount bracket.

[Tom E.]

[Dan B.]

Re: Body mount #4 Question

Thanks for the replies guys, and putting me in the right direction. I did some more research based on Mark's info and according to what I find, all 1963's used the same mount with the nut, and then beginning in 64, there was a separate mount for a coupe with no nut, and the convertibles had one. It would be easy enough for me to correct this now if need be. Hopefully some others with experience will confirm this.

[Joe L.]

Re: Body mount #4 Question

All-----


There's kind of an interesting story here:

1963 Corvettes, either coupe or convertible, used reinforcements GM #3824685, left side, and GM #3824686, right side. These reinforcements have the weld nut used for the deck lid hinge anchor point which is unused on coupes. I suppose it's possible, though, that the later reinforcements without weld nut were used for later 1963 coupes.

1964-67 used the following reinforcements:

GM #3853495, left side---with weld nut

GM #3824686, right side----with weld nut

GM #3853497, left side-----without weld-nut

GM #3737230, right side----without weld nut

Of course, the factory could have substituted the weld nut versions for coupes if they ran short of the non weld nut reinforcements.

C3 Corvettes used corollary reinforcements GM #3938133, left, and GM #3938134, right, for both coupe and convertible. Convertibles used an add-on bracket for deck lid hinge anchor point.

There are two interesting things about the above:

1) NONE of the above reinforcements, C2 or C3, were EVER available from GM in SERVICE. This is highly unusual;

2) The 1964-67 coupe right side bracket has a very strange part number. The 3737230 part number implies about a 1958 release. I can't imagine what application a very specialized part like this could have had in 1958. Of course, I am unable to research that since the part was never available in SERVICE and the application could have been for anything in the GM car and truck lines, not just Corvette or, even, Chevrolet although it is a Chevrolet part number..

[Dan B.]

Re: Body mount #4 Question

Thanks for that detailed reply Joe.

I decided to remove the nut, ground smooth and paint. I saved the nut so the next owner can always reinstall it if they want to

[Tom D.]

Re: Body mount #4 Question

PastedGraphic-1.jpg
Here is a Left side version, from a Corvette coupe built in March, 1965. The discussed bolt hole (exists in metal "nut plate") does not go through the fiberglass.

[Dan B.]

Re: Body mount #4 Question

Thanks Tom, that's what mine looks like now. Sealed the hole as well.

[Dan B.]

Thanks Rich Mozzetta

While we are on the subject of the #4 mount, there have been many posts about replacing the cage nut retainer (and or nut) and trying to do this with the above pictured reinforcement in place.

I came across a previous post from Rich Mozzetta on the subject and wanted to give him a BIG thumbs up for his cleaver use of small machine screws from the top to complete the retainer reattachment since the rivet heads are not accessible with the bottom plate in place. Great idea Rich, thanks for sharing that (and so many other well detailed repairs that you have done) just what I needed

[Richard M.]

Re: Body mount #4 Question

Dan, Glad that helped. I've done several convertibles that way over the years when not a body off.

Here's a example of the first time I used that process. About 8 years ago I worked on a blue '67 with clogged up decklid drains. This is the primary cause of the #4 nut cage well "ponds" and rust. This was just one side. Other side was just as bad.
P2220001.jpgP2220003.jpgP2200263.JPG

Then the fun begins. Getting the upper/outer bolts out of the decklid hinges is a trying task. Just the right combo of sockets and extensions help. Then you discover the mount bottoms and springs are nasty too and need attention.
P2200244.JPGP2200247.JPGP2200262.JPGP2200259.JPGP2220001.jpg


If the #4 cushion and thick washers and shims are removed and a wood block is strategically placed in the leftover gap, it's easier to drill the hole and to get the thread tap through. It's going through the old rivet head(which is sandwiched between the #4 mount and the underbody) and the steel #4 mount itself which is just thick enough to capture the screw.

This black car below was a body off so I riveted the cage. Ref pic of sandwich area which you cannot see on yours. Notice the depressions in the fiberglass where the rivet heads sit. #4 mount removed to access cage rivet holes. The rivet heads will be tapped along with the steel mounts on yours.
P7140045.jpgP7140044.jpgP7140046.jpg

#4 mount back in place. Bolt shown is to capture the #4 mount tightly while riveting.
P7140048.jpgP7140049.jpgP7140050.jpg


Back to the "Screw in" method.....
I levered the mount and added blocks to get at everything.
IIRC I used #10 machine screws and cut them so they're just flush with the #4 mount lower surface. Once the cushion and washer is installed you can hardly see the screw ends. A little black touch up paint and good to go. You can add a few washers under the screw heads to get it flush too.
P2230001.jpgP2230012.jpgP2240024.jpgP2240025.jpgp2240026.jpg

Rich

[Dan B.]

Re: Body mount #4 Question

Great pictures Rich.

I have the body on my Coupe raised (correcting prior body off by PO who missed a few things) to repair /replace the fuel line to a one piece line, brake line front to rear, and do the outer seat belt corners (none installed!). I have completed all these repairs and will be lowering the body back down shortly and fixing the cage nut plate when the weight is back on the mounts. Your method of using the screws is great since I am not doing this job on a lift and have the body raised on screw jacks. Mine was a prior body off done a while back by a PO, but he missed several items, so I was starting with a relatively clean and rust free platform and all the frame bolts came off easy. My goal was not to get into a complete re restoration but just to fix what was wrong and freshen it up keeping a narrow scope.

Second photo is a blob of sticky old fiberglass that Bubba did, third photo is cleaned re glassed body outer corner repaired area. Then installation of the new part. Got the corners from Paragon, made in USA. Beautiful well fitting parts. Cheers!

[Richard M.]

Re: Body mount #4 Question

Dan that's a clever lift method.

Nice looking repairs on the FG and those reinforcement look very good.

Rich
PS I thought that 1st photo you posted looked familiar.

[Dan B.]

Re: Body mount #4 Question

Hah yes!
Rich, you don't know how many times your pictures have helped. They are so detailed and well captioned that often I am finding answers to questions I was not looking for when doing a search.

My lifting method works great for repairs where you just need to get the body off the frame 8-10 inches which is plenty of room to do this work. I can turn each jack a bit at a time while measuring the vertical lift side to side and leveling front to back making it a one man job without any drama and a safe way to avoid body damage to a finished car.