Snapped bolt on frame cross member, any creative solutions?

Hey there. So, while installing a set of rock sliders today I managed to snap the head off the bottom bolt on the cross member supporting the drive shaft carrier bearing. Before folks ask,
yes I was turning the bolt in the right direction (triple checked that one before getting the larger wrench that ultimately broke the bolt). Why it broke is one thing, not sure about that one, what to do about it is the other. There are signs of corrosion on the underside of the bolt head, perhaps the threads are solidly rusted in, a bit worrisome since the truck is only a 2017.

Needless to say the remaining bolt shaft is good and stuck in the nut that is welded to the backside of the cross member. Soaked the thing in WD 40 at the beginning of all this and have tried a bolt extractor and that thing is not coming out forwards or in reverse.

I figure I can completely drill the old bolt out, likely destroying the welded on nut in the process, which is fine. Another option is the welded nut is only spot welded at the corners and I was considering simply trying to break the nut loose from the cross member. It is a square nut which is a bit unfortunate, limiting tool choice a bit. Perhaps a cold chisel might work as well to knock the nut off. Then I could just throw the nut/bolt combo out and start with a new bolt and nut. I am trying to avoid drilling the whole thing out since it seems like it would be a serious pain but was also unsure if I could break the welded nut off. There is not a lot of space for tools in there.

I am considering my options and was wonder if folks had any creative ideas.

Photos of intact passenger-side bolt and cross-member nut

 

WD40 is not going to do much to loosen a rusted bolt. Try PB Blaster or Kroil Penetrating Oil. If no luck try heat if safe to do so in that area.

Edit: unfortunately these are the things you should have done before going to town hard on that bolt head. But you may still be able to use a speed out bit after prepping with the above materials and heat.

 

I would not break the weldnut. I would use a nice fine punch and start you a pilot divot as close to center on that bolt as possible and CAREFULLY begin drilling it out starting with 1/8 inch bit and working up, use good quality bits and correct drill speed and pressure.

Also consider heat shocking that bolt, use a torch to heat it up to 500deg F then quench it with WD40 or PB blaster do that 3-4 times then try drilling and use reverse bits if you can.

When you get the bolt shank out then chase the threads in the weld nut with a lubricated tap.

I’ve had plenty of success with this method.

Were you trying to take the bolt out or put it in?

 

Best penetrant I have used is Beo-Sheild T-9.

 

Drilling bolts is a serious pain in the ass unless you have the right tools. Heat is usually the best option, but it’s a bit late for that now. Also for future reference WD40 is NOT a good penetrating fluid, there are plenty of way better products. PB blaster is decent and readily available at any auto parts store.
If you don’t care about the paint, then heat, quality drill bit and extractor might work, as you said breaking the weld nut might be your best option, but even that might be harder than you think, maybe hit two of the welds it “looks like” you can get at with a dremel. Then an adjustable wrench on it.

 

Having done this on a part from a Tacoma removed from the truck and in a bench vice... Good luck.

Them weld nuts are *REALLY ON THERE* those little machine tacks are more stout than you would expect just looking at them.

(I removed the weld nuts from the front frame lower extension “wings” to reuse them for something else, I ground them a little with a dremel and carbide bit and tried to twist them off with a big adjustable crescent spud wrench and ended tweaking the plate rather than snapping them off, brought out the 4” grinder and gave them hell.)

 

Heat.

 

Taking it out. I was pretty surprised when the head snapped, it broke without a ton of force being applied.

Good point about the WD 40, I'll soak the other bolt with something else before taking that out.

I was a bit reluctant to put a torch on it, there is a wiring harness nearby as well as all that caulk you can see inside the frame rail from Toyota. But some heat certainly might help.

 

You can use aluminum foil as a heat shield for anything nearby and use a heat gun at point blank rather than a torch if you have to, just be careful and deliberate. If the nearby wires are O2 sensor wires they are made different and have a much higher heat tolerance although nothing is flame proof on the truck.

 

Weld a bolt on to it.

 

I was afraid folks might say that!

A heat gun is a good idea.

So a good course of action could be a couple rounds of heat and PB blast, followed by the bolt extractor again.

I like the idea of being able to drill it out nicely and re-tap but seeing how I'll be doing this under the truck it sounds like a tall order to pull off.

 

What everyone mentioned this far, additionally pick up some left handed drill bits. Many times when you get close to the minor diameter, the bolt will grab and spin right out. Another thing is heat, then spray as it will draw the foofoo spray in there. Another trick; try rattling the not broken one in a clockwise direction ever so slightly before reversing it out.

 

Having done it a few times I can tell you overhead drilling is *NOT* fun.

Gloves, long sleeves and a face sheild highly recommend, safety glasses and ear plugs mandatory!

Exhaust bolts are the worst, I drilled out all my studs after snapping a few and replaced them with high quality stainless through bolts bathed in nickel anti-seize.

A little sliver of hope, usually after drilling 1/4" bit in a m12 bolt there's enough material loss for the bolt to "shrink" in on itself and it will thread out with the drill bit and you never have to get real close the the threads.

 

If you take a disposable or old shallow bowl and drill a hole in it, then you can hold it up and drill thru it and it catches most of it.

 

Yeah welding/placing a new nut on top of the old one...I was considering that if I get to the point where the only option left was to drill the entire bolt out with a wider bit destroying all the original nut's threads in the process. An option but not one I was keen on.

EDIT: thought you said weld a nut on top, Interesting idea though with a bolt, then just use the new bolts' head to get a wrench on it and drive the old one out?

Unfortunately these is no space to do that, this is inside one of the cross members, there is only maybe 3-4 inches max worth of space in there.

 

Yeah I deleted my post when I went back and looked at the pics.

I will add that my welded nut just popped free. Maybe try taking a punch to it, or air chisel. If the same weld job is on yours that's on mine, you might get lucky and be able to break the welds.

Maybe.

 

Okay I've done a lot of aviation rework and here's what I'd do.

Use a drill bushing set. One with a ID of the exterior diameter of the nut, so that you can then put a slip fit bushing(drill guide) into the bushing and be perfectly center. Then drill out the stuck bolt slowly from a 1/8 size stepping up untill you've drilled almost to the threads of the nut. Usually you can clean out the rest of the bolt which is left in the threads of the nut at this point. This wouldn't require any welding but getting the bushings can be hard, there's pakces you can order custom sizes though.

Also before even drilling to the threads of the nut you can obviously try a bolt extractor which will now be perfectly center in the bolt, and strait with the drill bushing as a guide, usually that'll get it out before you have to drill further.

 

If I was in your position, I'd weld a fender washer to the broke stud then weld a nut to the washer. I'd try that 2 maybe 3 times. If that failed I'd beat that mf out of there and throw a nyloc on the backside. Always good getting a lil (in your case, a lot) of aggression out.

 

Another very handy tool is a hammer style impact driver. Whether on a budget or not, I have one and it has worked for me in places where I couldn't otherwise get my cordless impact. ETA think those hammer style impacts can be bought for $20.00

 

What nut? Also, how would u hold the drill guide?