Crossmember frame captured nut repair?

[Ks65stang]

I broke off two of the eight bolts when removing my transmission / t-case crossmember. Today I drilled them out and will attempt to re-tap the threads. If this is unsuccessful, what did you do?

I considered drilling through both sides of the frame and using a longer bolt but I will have to take care to not crush the frame.

 

[Apogee]

What are your capabilities with respect to metal fab, welding, etc? There are several ways to "fix" the issue, but all of them will require a certain amount of varying degrees of invasive surgery on the frame. I tend to default to threaded sleeves through tube sections, as that allows you to properly torque the fasteners to full torque and not risk crushing the tube, but that involves machining the threaded sleeves, drilling the frame to match and then welding it in on both sides (assuming you have access to both sides).

 

[Ks65stang]

I have some fab skills and equipment but its not worth too much time. I like the sleeve idea, but I may just weld in a sleeve and use a nut on the outside frame.

 

[Jfryjfry]

Try a rivnut first. If it doesn’t hold, you’ve lost nothing other than some time and the cost of the nut

 

[Jfryjfry]

Also, you can try retapping to whatever metric bolt is just larger than what you have as it will/could cut fresh threads without taking much metal away

 

[bronkenn]

Those aren't to hard to drill and tap. I had to do a couple of mine. Take your time and use a good tap and it will be fine.

 

[Rustytruck]

https://www.mcmaster.com/thread-rolling-screws/thread-forming-screws-for-hard-metal/

 

[Ks65stang]

Never used a Rivnut. I’ve seen them on TV. Norther tool has them cheap and that looks like a tool I need to own but it may not work w/ the thickness of the captured nut factory welded on the side of the frame. I’ve also never used thread cutting bolts. Are they only sold in Metric? Even if I don’t use all these ideas and go old school, these idea are educational ideas. Thanks.

 

[Rustytruck]

You can always weld up the holes and drill and retap.

 

[Rustytruck]

sorry try these. I used these on my transfer case skid plate welded up the frame holes drilled and drove them in.

https://www.mcmaster.com/self-tapping-screws/steel-hex-head-thread-cutting-screws-for-metal/

 

[Steve83]

When I moved the Xmbr on a '75eB, I hole-sawed the bottom of the frame for access to install common loose hex nuts on the bolts. You could do the same to add hex nuts behind the stripped welded frame nuts, then tack-weld the hex to the frame nut.

(click this text)

 

[thegreatjustino]

Helicoil

 

[73azbronco]

Never used a Rivnut. I’ve seen them on TV. Norther tool has them cheap and that looks like a tool I need to own but it may not work w/ the thickness of the captured nut factory welded on the side of the frame. I’ve also never used thread cutting bolts. Are they only sold in Metric? Even if I don’t use all these ideas and go old school, these idea are educational ideas. Thanks.

I have a really nice rivnut tool, but would not want to use it on anything structural like tranny mounts. It’s more for fender flare mounting type stuff.

 

[73azbronco]

Helicoil

This^^^. Aren’t they some other name though now, you young whipper snappers you.

 

[Ks65stang]

I was able to drill and tap. Wasn’t perfect but it worked. Didn’t use any ol that fancy stuff.

 

[DirtDonk]

This^^^. Aren’t they some other name though now, you young whipper snappers you.

Didn’t know that they had changed, but there have been two or three other well-known brands over the years in addition to them. Time Serts, Keen Serts(sp?) and at least one other.

 

[bronco italiano]

If you can deal with Metric, these are structural rivnuts by Audi. I use them for heavy apps but I also weld the large outer area too.
https://dieselgeek.com/products/m10...fkDD2B3zx0A2YSiLy0SJTZCy-GeIDWgCBCMt6i_Rhz7k4

 

[DirtDonk]

That’s a great idea!
Like a weld-nut, but can be set in position and worked with even before welding.