1970 Cadillac convertible spare tire stowage

[Roman Z]

Since I purchased this car the spare tire was just floating around the trunk. My jack is stowed next to the quarter panel. But I see no
fastener on the trunk floor. I presume, looking at the picture on the trunk lid  there was a threaded rod that screwed into the floor panel.
I have the large wing nut, but no threaded rod. Was there an insert on the floor pan?
Thanks.

[35-709]

Your hold down should probably look like the one in the link below.  There is no threaded insert in the floor,
just an upside down "U" shaped attach point welded to the floor to slip the "J" rod into. 
Used by GM for many years, my '68 Bonneville convertible is much the same.

https://shop.advanceautoparts.com/p/dorman-help-spare-tire-hold-downs-41068/5014026-p?c3ch=PLA&c3nid=5014026-P&adtype=pla&product_channel=online&store_code=&gclid=Cj0KCQjwwNWKBhDAARIsAJ8Hkhc5x20R8VCovvs_FoKWOjp5U_8JDfryRh8MZ9aQwH1wkqIP7f4afOAaAld4EALw_wcB&gclsrc=aw.ds

[Roman Z]

Unlike the sedans, the convertible is stored next to the right quarter panel. I understand the bracket mentioned. I had those when the tire was mounted center under the rear glass.
Under the carpet there is no fixture that would except a u-shaped bolt.

[35-709]

OK, someone with a '70 convertible here should be able to help.

[fishnjim]

https://images.skinnerinc.com/full/840/1106840_view%2005_05.jpg
http://www.significantcars.com/cars/1970cadillac/trunk.jpg

[35-709]

Yup, that is what I was referring to --- same as my '68 Bonneville.

[Roman Z]

that's exactly it. So my original question is how is that threaded rod secured to the trunk bottom? And what does the threaded rod look like?
There's no evidence there ever was a fixture welded in that area. There is a small 3/8" hole there. Perhaps it was a square fastener that snaps in place with a 3/8" threaded nut.
Thanks,

[Roman Z]

Maybe something like this cage nut.

[The Tassie Devil(le)]

I have only ever seen the welded ""U" shaped piece on the floor, and the rod is a threaded piece with a hook on the end to engage the welded piece.

The Owners Manual should show you what is there, in the section on changing a tyre.

Bruce.

[Roman Z]

unfortunately the manual doesn't show the breakdown.

[Cape Cod Fleetwood]

Since I purchased this car the spare tire was just floating around the trunk. My jack is stowed next to the quarter panel. But I see no
fastener on the trunk floor. I presume, looking at the picture on the trunk lid  there was a threaded rod that screwed into the floor panel.
I have the large wing nut, but no threaded rod. Was there an insert on the floor pan?
Thanks.

Roman go on Facebook, go to the "1965-1070 Cadillac Collective", John Abend is the moderator and few know these cars better than he. And he's probably got the part you need too. Let us know what happens.

[35-709]

Don't understand that "u" shaped piece in the floor not being there.  Perhaps the trunk had some floor replacement work done and the attach piece was never put back? 
The threaded rod with the hook that attaches to the floor will look much like the one I linked to in my first post above.
I will go out and take a picture of what I have and post it in another post soon.

[35-709]

Pics below of the threaded "J" hook and floor attach point

[fishnjim]

Is there no '70 authenticity manual?
Is there an attachment place on the jack support for it?   
Apparently you don't have the OEM hook?     
There's a picture of a '70 spare tire rod (ebay) and it's not the usual suspect "J" hook - we all know and recall.   When you look up the hold down replacement, it does not cover '70 Cadillac, all other period GM.   So could be one of those weird ones.
So someone with one or a judge will have to clear this.   
ps: The "J" hook and "J" hook hold down are reproduced.   Needs to be welded in.   But may not be correct.   

[Roman Z]

This what is under the carpet. If there was work its not evident.

[35-709]

   Your picture, copied below, shows an area that I have circled where the attach point may have been but has pulled off.  Doesn't seem very likely but really just grasping at straws trying to solve the puzzle you have presented. 
Sure would be nice if someone with a '70 convertible would post a picture of a stock spare tire hold down configuration.

[35-709]

I DO have a '71-'76 Authenticity Manual    Whether the '70 and '71 hold downs are the same or not I cannot say, but the '71 appears to be the same as most other GM cars of that period.  A picture of the correct '71 pieces is below. Once again, the "J" part of the threaded rod goes into a "u" shaped or short tubular shaped piece welded into the floor.

[Cadman-iac]

The problem with using a 71 and up authenticity manual for a 70 convertible is that there was no convertible in the Deville body for 71 and up. And the tire location is different for a  coupe or sedan.
My 69 Deville convertible had the spare on the right side of the trunk. You can't put it up between the wheel wells because of the top and back glass.
Unfortunately I don't have any pictures of mine anymore. I sold it in '87.
  35-709 is correct about the type of anchor used on the floor. But the location circled in the picture is too close to the rear of the car for the tire to be anchored to. It should be farther forward of that location, if I'm judging the distances correctly.
You can place your tire in the location shown in the label, then look directly down through the center of the wheel and your anchor location should be very close to that point. Clean the floor and look for possible broken spot welds where it might have come loose.

  Rick

[Roman Z]

It turns out the trunk deck was replaced at one time and the anchor point is not there.

[35-709]

"Perhaps the trunk had some floor replacement work done and the attach piece was never put back?"