TR2/3/3A Why a PO cut these holes in rear floor? Also, question re dealing with captive nuts

[wifegonnakillme]

I have matching holes cut in the rear floor of my '56 - seems odd to me as they are matching and not is a spot of typical rust.. maybe they tried to add rear bench supports? Anyway, that's a curiosity.

My question is regarding the favorite way to deal with broken bolts in captive/caged nuts. One of the POs in their separating of the various panels broke the majority of the bolts for the body panels (85% of them). I could spend hour drilling and tapping, but I am not going for concourse and really don't want to spend the limited time I have for this doing that... I could weld new nuts on, but I wonder if I need that bit of movement for lining up panels.. I am leaning toward trying to drill the overlapping metal, replacing the bolt and then spot welding it back... experiences?

 

[TR3driver]

In many places, that little bit of movement is important. I've had to deal with DPOs welding in nuts, and I always find it aggravating. The original cages are also prone to spreading and letting the nut turn, which is also aggravating (to say the least).

The approach I've taken is to buy "Easy align weld nuts" from MMC https://www.mcmaster.com/?m=true#90955a113/=1411gfd and either spot weld them in place, or attach with pop rivets. The ones I got do have a protrusion around the opening, which means you have to either open up the hole in the sheet metal, or grind the protrusion off. Both approaches work, but I usually open up the hole.

Usually easier for me to grind away the old cage rather than trying to drill out the spot weld. In some cases, I've been able to just pry it off after cutting through the nut with an angle grinder and cutoff wheel.

Use plenty of anti-seize when you put the bolts back in, so they come out easy next time. I prefer the copper-based stuff, but anything is better than nothing.

PS, there's a write-up on the weld nuts at https://www.macysgarage.com/myweb6/cage_nuts.htm Macy will also sell single nuts (have to buy a box of 10 at MMC).

 

[CJD]

The cages and nuts are readily available from the big three suppliers. I've had several wings that had a 15% success rate, so that is not uncommon. You will get VERY proficient replacing the nuts and cages. This is one area that concours or not makes no difference, as few show once the car is together. Their sole purpose is for YOUR convenience on the re-assembly, so I personally would not consider not replacing them or eliminating the "wiggle". Doing so will only cause you untold grief later.

...The holes look like access to mount a roll bar/cage through to the frame.

 

[TR3driver]

Oops, forgot to mention: The nuts & cages I got from TRF did not fit each other. Nuts were a little big, cages were a little small; result the nuts didn't fit inside, let alone provide some wiggle room.

That was a few years ago, tho, so maybe they've got the issue fixed by now.

 

[wifegonnakillme]

30 caged nuts ordered... will be fun trying to remove the old ones from the upper dogleg, I think I will drill from the front to weaken the connection, then hit with a chisel from behind, then use the holes for spot welds.... Will hopefully be cutting the first fresh metal later today. Its a funny car, has rust in places I wouldn't expect and yet has really nice fenders and even repairable rockers... but there are signs of a previous accident, so the fenders might not be original.
Thx, Kerry

Thanks John re the holes in the floor, didn't think of that - after looking at Terry's car, I've been contemplating roll cages - maybe I'll patch there last...

 

[malbaby]

This suggestion may work for you.....how about using what I call rivnuts close to the existing holes.

 

[tdskip]

Good luck with the project, and good source Randall.