The bolt attaching one of the pressurized struts that holds up the back of my minivan lift gate sheared off yesterday, and I need to drill it out.
I’ve never done this before, but it looks pretty doable via youtube. What I’m hoping for is a recommendation on which tools to buy. Looks like I need some left-handed drill bits and an extractor tool. There are numerous sets on Amazon, but I don’t want to either buy junk or spend hundreds of dollars on it (unless I have to spend hundreds of dollars, in which case I’ll probably pay a mechanic to do it).
I’ve only used it a few times, but I’ve had really good luck with this one:
[EDIT: HD doesn’t seem to carry them any longer. Link removed]
But … FWIW … depending on your comfort level in doing this, you could probably get a mechanic to weld a nut onto the remainder of the bolt for a very few bucks (think: twelve-pack of beer) and the just use a wrench to back it out yourself.
Is there any of the bolt shaft protruding, or did it shear flush?
The hardest part about using a screw extractor is drilling the pilot hole - it’s often ver hard to drill it reasonably on-center into the old bolt. You don’t want to mess up the threads in the hole.
Pretty close to flush. The shear line is unfortunately not flat which makes drilling that center pilot hole a challenge, but there’s not enough sticking out to grab with anything.
I do have a call out to a mechanic, so hopefully they will be able to do it for a reasonable price.
Last year I needed to extract a broken-off exhaust bolt on a cylinder head.
I have a bolt extraction kit, and I’ve used it with success. But this bolt was pretty small, and I knew if I didn’t drill the pilot hole correctly I could really mess it up. I didn’t want to take the risk, so I took the cylinder head to a machinist, and he extracted it for $40.
First use a spring loaded center punch to make sure you’re in the center of the bolt. Automatic Center Punch
Just about every hardware and home improvement store should stock them. Amazon if you have to.
Then go in with around an eighth inch drill bit for a pilot hole. You don’t have to go all the way through the bolt, just deep enough to ensure your bolt remover bit won’t walk.
Finally, go with whatever bolt removal solution you decide on. Just make sure you use the right size. Too small and you’ll wind up with a piece of hardened steel broken off in your workpiece and that absolutely sucks.
Also, soak it with penetrating oil for a day or so before you try to extract it.
Flood it with oil, and tap it with a hammer a bunch of times.
If the head broke off, it’s likely rusted and seized.
Oh, man! This kind of repair is difficult on a flat, horizontal surface. I can’t imagine what you will face on a a rear lift gate. And I wouldn’t hold out much hope on a ‘reasonable’ price from a “professional”.
You may end up going full Frankenstein on this (JB or actual Weld). Best Wishes and Good Luck!
My sympathies to your plight.
In the past I’ve had success using a cold steel chisel to either knock a bit off the broken bolt, in order to make a flatter surface for drilling, or, several times I was able to use the chisel and hammer as an impact wrench sort of deal and back the broken bolt out a few turns, enough to grasp it with pliers or vice grips and turn it out the rest of the way.
I will second the spring loaded punch mentioned above to give you a little starter dimple to help keep the drill bit from walking
Thank you all for the suggestions. It turns out I had an even better solution, which was that I’ve been trying to sell this van for over a month and today someone bought it. So the sheared-off bolt is now officially Not My Problem.
Wow! That sounds dicier than drilling a hole on center. I guess if you have an angle grinder, though you can try it more than once, unlike the pilot hole.
if the stud is broken off below the surface of the hole and there’s nothing to grab onto, the trick is to put a washer over the end of the hole, wire-feed-weld into it, fill up the little cup with melted welding wire, weld a nut onto the little mound, and then unscrew it.
