Snapped liftgate support bolt. Ideas? (1 Viewer)

[LX Cruiser]

I replaced the tired liftgate supports today. While removing the right side, one of the support bolts in the liftgate snapped. I was very surprised by this because I wasn’t torquing on it very hard at all. It was mid-40s ºF when I did it. Maybe that had something to do with it. Also, it kinda looks like it has red threadlocker on it.

How would you tackle getting this out? I had to wrap up because it got dark. I’m wondering if I can get at it through the backside by removing some trim pieces around the rear window. I have taps that can back out a bolt with a snapped head. But the surface of the snapped bolt is domed, and my bit just skips right off of it. Frustrating. The bright side is, the liftgate goes all the way up now.

 

[tbisaacs]

Can you use a center punch to notch it so your bit will stay put? Or maybe a Dremel with a carbide bit?

 

[bloc]

Get a carbide tipped center punch to make your initial drill mark.

I don't believe accessing it from the back will help much, as typically only the thinner end of the bolt will protrude through the captive nuts. There won't be enough to get ahold of.

The other bolt does look a bit like loc-tite but I have no idea why they would do that. These things don't seem to have a tendency to just loosen up randomly. If it's high-strength locker heat will be necessary to remove the broken bolt.

Even if there is no loc-tite I've found those black bolts do have some kind of degradation in the threads, where when they let loose there is a bit of a snap. I could imagine whatever is causing this progressing too far eventually and seizing up a bolt.. When the other let go was it sudden or did it loosen normally?

And to be clear, it broke when loosening or tightening?

 

[John McVicker]

I don’t have a 200, so I don’t know…but ‘if’ you can get to it from the back side, I would consider that.

Looking at the other bolt. It appears as if you have enough sticking out to grab it with some Vice Grips. I would also use penetrating oil…NOT WD40.

 

[LX Cruiser]

Can you use a center punch to notch it so your bit will stay put? Or maybe a Dremel with a carbide bit?

Great idea. I have those tools.

 

[LX Cruiser]

Get a carbide tipped center punch to make your initial drill mark.

I don't believe accessing it from the back will help much, as typically only the thinner end of the bolt will protrude through the captive nuts. There won't be enough to get ahold of.

The other bolt does look a bit like loc-tite but I have no idea why they would do that. These things don't seem to have a tendency to just loosen up randomly. If it's high-strength locker heat will be necessary to remove the broken bolt.

Even if there is no loc-tite I've found those black bolts do have some kind of degradation in the threads, where when they let loose there is a bit of a snap. I could imagine whatever is causing this progressing too far eventually and seizing up a bolt.. When the other let go was it sudden or did it loosen normally?

And to be clear, it broke when loosening or tightening?

Loosening. I think you’re right on the degradation. It looks like it could be rust instead of red loctite. If it’s loctite, then I would assume these supports have been replaced once already. Surely red loctite isn’t a factory thing.

 

[bloc]

Surely red loctite isn’t a factory thing.

Surely not. Maybe a low-skill shadetree thing.. but unneeded.

 

[TeCKis300]

Bummer. These bolts do have loctite on from the factory.

 

[GordJ]

Has anybody used the reverse cut drill bit idea? It kinda appeals to my sense of logic but I have never known anyone who has used it.

 

[bloc]

Has anybody used the reverse cut drill bit idea? It kinda appeals to my sense of logic but I have never known anyone who has used it.

I have. Great when you simply used too much torque and napped the head off but the bolt doesn’t have anything solidly holding it in place. Won’t make a difference when something is locking the threads.

Welding would be ideal but difficult in this location and may damage the paint.

Center punch, very careful drilling, and proper use of a bolt extractor should get this done.

 

[CharlieS]

Shouldn't be any different than removing any other broken bolt that is below the surface, except you will want to be careful with heat so you don't damage your paint.

Most important step: Center punch. Get that right and the rest is cake.

Drill slowly with well sharpened, incrementally larger drills and cutting fluid. With any luck the heat and rotational movement of the drill will cause it to go through the other side and drop into the body cavity. Even if it doesn't you should get to a point where you can stop and pick the old threads out, re-tap and go. Worst case you helicoil it or similar - this isn't a critical fastener.

Find the nearest garbage bin for those extractors. I've never had one of that style work, and I've had several make a crappy job a very long and crappy job. They are very hard and brittle material, so once you break it off in the fastener, you have fun drilling that out too.

 

[CharlieS]

One more though is that if you weld, you could make a quick drill guide that bolts into that other bolt hole and indexes your drill center to make sure it stays centered on the broken bolt. Even if you don't weld, you could make a simple drill guide with a piece of flat stock.

 

[LX Cruiser]

Bolt extractor snapped off in the snapped off bolt. Lol.

 

[CharlieS]

See post #11. I've seen this movie before.

Good luck.