Broken Captive Nuts (1 Viewer)

[C6H12O6]

Long story, short: I broke off a bunch of bolts in the floor pulling out the seats and gas tank. Drilled most of them out with no issue, but one of them ended up with a broken tap inside the hole, and the other ate a drill bit on the way to the tap. Tried drilling them out. No dice.

Tried hammering the with a punch to shatter the hardened bits, but that ended up with the captive nut punching out the backside of the hole. Normally, not a huge deal, but (of course) both are in places that I can't get to from the other side. Both are for the hold-down bolts for the gas tank cover. One in the door sill that I can't get behind, and one just on top of the boxed portion of the floor on the raised back section. Again, no access from the back.

So... options?

Just hold the cover down with the other five bolts and ignore them?

Nutserts in the hole?

Something else?

 

[Alexh85]

Nutserts are probably the best way to go.

 

[JohnBoy]

It water over the dam but I've been there and feel your pain. I always spray any project I'm working on with Kroil, or PB Blaster, several days before I start my project. It's made my life easier. X2 on the Nutserts recommendations.

Good luck, you'll get it.

 

[spotcruiser]

You can weld on new captive nuts. McMaster Carr has them in a couple of different styles.

McMaster-Carr

I just used a set of these to add threaded holes on top of my windshield for a softtop channel. I drilled holes to fit the flange of the nut and welded the outside circumference of the flange to the original sheet metal.

If you wanted to use a different style, you could weld a nut to a 1" x 1" piece of sheet metal and then weld that whole piece into the truck.

 

[C6H12O6]

Thanks. I have pretty much been soaking them in PB Blaster for weeks leading up to their removal. Most of the rusty bolts I could wire brush the back sides before removal. The worst ones didn't have any back-side access and the rusty exposed threads jammed up part-way out. Bummer, but pretty typical.

I'm thinking nutserts would be the easiest way to check this box. If they were going to be visible or were load-bearing in any mission-critical way, I'd probably weld something in, but these two holes are just 2/7 of the hold-downs for the gas tank cover. I'm not too concerned, other than the old nuts jingling around in there, driving me nuts.

 

[reddingcruiser]

Unless this is a concourse restoration I would use Nutserts. Quick and easy!

My son is going through the exact same issue with his tranny cover and is grumbling about using nutserts (he's just jealous mine are all OEM ).

 

[sproggy]

Thanks. I have pretty much been soaking them in PB Blaster for weeks leading up to their removal. Most of the rusty bolts I could wire brush the back sides before removal. The worst ones didn't have any back-side access and the rusty exposed threads jammed up part-way out. Bummer, but pretty typical.

I'm thinking nutserts would be the easiest way to check this box. If they were going to be visible or were load-bearing in any mission-critical way, I'd probably weld something in, but these two holes are just 2/7 of the hold-downs for the gas tank cover. I'm not too concerned, other than the old nuts jingling around in there, driving me nuts.

...Nuts about nuts.

 

[FJ40Jim]

The broken part is a caged nut or self-aligning nut.

McMaster has them.
McMaster-Carr

 

[C6H12O6]

Not sure how I’d install that. I’ve seen those other places on the truck (taillights), but it seemed like the broken nuts were welded in like the ones under the tranny hump.

Drill the hole big enough for the nut to drop through and weld the strap in on the surface? Seems like that would be more visible and rust-prone from the back side than a nutsert.

 

[FJ40Jim]

Grind off the old welded cage.
Weld on new cage.

Factory used a spot welder. I just do a little MIG weld on the edge of each ear.

Edit: I just re-read first post, realized there's no access to the backside to weld.

If there's any access, then just use a regular nut & bolt.

 

[C6H12O6]

So, from the back side? I can't get into either spot from the back. One is in the door sill where the gas tank cover bolts down; the other is in the boxed-in area on the front of the raised back section of the rear floor, again where the gas tank cover bolts on. Otherwise, these look pretty slick.

 

[FJ40Jim]

Sorry, I was confused about the location. I thought we were talking about the cage nuts underfloor for tranny cover.

For the gas tank cover (which is really the fuel tank hold-down straps), the weld nuts, as shown in post #4, would be the easy button.

 

[C6H12O6]

My truck is a ‘74. I didn’t have any additional straps in there. Just the cover. Should there be straps?

 

[rkymtnflyfisher]

My truck is a ‘74. I didn’t have any additional straps in there. Just the cover. Should there be straps?

No. Not if there is a cover.

 

[MOTOV8R]

So, from the back side? I can't get into either spot from the back. One is in the door sill where the gas tank cover bolts down; the other is in the boxed-in area on the front of the raised back section of the rear floor, again where the gas tank cover bolts on. Otherwise, these look pretty slick.

If you are set on replacing the captive nut. Cut out the section around the nut, weld on a new one, weld the cut section back in place.

 

[rkymtnflyfisher]

Cut out a patch on the outer rocker! Weld in the new nut, treat the inside of the rocker area, weld in the new patch, and paint.


Or use a nut-sert.

 

[raymond2335]

I've been there.... I just drilled a hole to the exact size of a nut then held the nut flush with surface (most of the nut is below the surface) and welded carefully around circumference of nut, grind and paint. Its a pain for sure but it is also motivation not to break off bolts!

 

[thebigredrocker]

@C6H12O6 I think FJ40Jim was just helping us expand our cruiser knowledge that the “cover” is primarily there to hold down the tank like earlier tank straps.

 

[C6H12O6]

Gotcha. That's what I thought, but since I am days away from reassembling the tank and cover, I thought I should clarify to make sure I wasn't missing something. There are a bunch of people on this forum I don't second-guess. Jim is one of them.

 

[MOTOV8R]

Gotcha. That's what I thought, but since I am days away from reassembling the tank and cover, I thought I should clarify to make sure I wasn't missing something. There are a bunch of people on this forum I don't second-guess. Jim is one of them.

You don't tug on Superman's cape
You don't spit into the wind
You don't pull the mask off that old Lone Ranger
And you don't mess around with Jim