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removing stripped allen bolt

slik560

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I stripped out a 6mm allen bolt when the allen socket and wrench slipped. It's in a very tight area at the back of the motor on my Mercedes 560SL and I anticipate using a regular screw-type extractor with an extension to reach the bit and vice grips to turn it. I don't think my DeWalt 18V drill or the impact driver will remove it. The other of the two bolts came out with a really healthy pull on the socket wrench. but I goofed on the second.

Had I sprayed a little Kroil on the 27 year old bolts prior to, I might have avoided this but....too late.

the head on the bolt inself is round; the allen socket hole is rounded now due to the wrench slipping.

Any feedback of a constructive nature appreciated. :D

Thanks
 
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Techie1961

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Drive a torx in it.

This is the best idea but I would use a drift first and give it some really good hits with a hammer before trying it. You want a drift that is as big as the screw head diameter. This will loosen the back face of the head where it is sitting and give you less torque needed.
 

franzdom

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cut the head off with a dremel, then vice grips after the threads are exposed?
 
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slik560

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All great tips. THANKS! I may look into the turbo twist first. As far as the Torx suggestion, I will have to take inventory to see if I have a suitable drift to use. Much appreciated ;)
 

MG44

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We always try a turbo socket type first on torx or Allen heads that are stripped.

Such a stupid design for a fastener and the euro manufactures love them unfortunately.
 
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slik560

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AND this one is in a very tight place. I'd post a pic, but it's a hassle on this board. Since I have two MB's I may as well pick up a set of Turbo Twist or similar sockets. By chance does metric make a difference? Probably just overall size. Find one that fits

Thanks again
 

bcradio

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cut the head off with a dremel, then vice grips after the threads are exposed?

That sounds scary to Dremel off the only part of the bolt you can grab onto

You might be able to Dremel a slot across the bolt head and use a hand impact driver to get it started
 
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slik560

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I will be lucky to find a turbo twist socket that will fit down over the round allen head that is shielded by this bracket for the crank sensor that I'm trying to replace. I'm not going to rush into this since the car runs well....until the crank sensor acts up. :)
 

404

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Bond in a short piece of hex wrench with JB Weld and use a socket on the hex stub?
 

VictorBravo

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I had something similar on an 8 mm bolt attaching a turbo down pipe to the turbo housing on an Audi.

Tried the Torx and stripped the torx teeth.

Tried drilling and basically dulled the drill repeatedly.

Tried a cold chisel, and flattened the edge.

Burnt out a dremel trying to cut off the head.

It was one hard bolt, for sure.

Finally took a small cutting torch tip and heated the head red hot and just lightly blasted it.

Odd thing, when I finally got the flange off, the remaining stud twisted right out with my fingers. That tells me that heating it and letting it cool might be a good start before trying to destroy things.
 

MAD

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For stripped 6mm, try driving in a 1/4" Allen socket. I have a 1/4" hex socket that the drive end is all mushroomed from doing this so many times.
 
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slik560

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I have the strong suspicion, given the number of allen bolts within the engine bay alone, that I will probably end up trying all of the above....except perhaps the induction heater...eventually. ;)
 
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nicksnothereman

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I stripped out a 6mm allen bolt when the allen socket and wrench slipped. It's in a very tight area at the back of the motor on my Mercedes 560SL and I anticipate using a regular screw-type extractor with an extension to reach the bit and vice grips to turn it. I don't think my DeWalt 18V drill or the impact driver will remove it. The other of the two bolts came out with a really healthy pull on the socket wrench. but I goofed on the second.

Had I sprayed a little Kroil on the 27 year old bolts prior to, I might have avoided this but....too late.

the head on the bolt inself is round; the allen socket hole is rounded now due to the wrench slipping.

Any feedback of a constructive nature appreciated. :D

Thanks

Heat then penetrating oil, pound an oversize hex bit (or socketed bit) in there then take it out with a t handle or ratchet (if it's a socketed bit).
 

Freeborn John

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Drive a torx in it.

I'm just surprised it wasn't a torx in the first place, Mercedes love them, both internal and external.
A torx or a star drive are probably favourite, after first soaking, tapping, heating and anything else you can do to loosen the little rascal.
 

stage20

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Epoxy in an allen key and let it dry. When all other things mentioned fail, if you can grind a slot in it. get a big flat head on a 3/8 drive and use it like you would if it was still allen.
 

n8n

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Craftsman Bolt Out saved my *** on a similar problem - stripped Allen head on some supercharger mount screws for a VW Corrado, if it hadn't worked I would have had to tear the front of the car apart to even get a right angle drill in there but they came through in the clutch. Similar to SK turbo sockets. I bought the "impact grade" ones.
 

joeysh03

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I had something similar on an 8 mm bolt attaching a turbo down pipe to the turbo housing on an Audi.

Tried the Torx and stripped the torx teeth.

Tried drilling and basically dulled the drill repeatedly.

Tried a cold chisel, and flattened the edge.

Burnt out a dremel trying to cut off the head.

It was one hard bolt, for sure.

Finally took a small cutting torch tip and heated the head red hot and just lightly blasted it.

Odd thing, when I finally got the flange off, the remaining stud twisted right out with my fingers. That tells me that heating it and letting it cool might be a good start before trying to destroy things.

Problem you had is that bolt is heat treated to with stand the extreme temperatures at the hot side of the turbo. Its a hardened steel bolt.

I had the same problem on an evo 8 turbo hot side. I was removing the but off the stud and it was stripping the threads. I had to use a HF breaker bar to get the nut off while prying up with a pry bar. My IR2135 would not remove it. I was going to put a die on it and use a smaller but till I read how long that would take I just bought a used one.
 
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slik560

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Post script: found a friend locally with the right removal socket. Former MB mechanic. ;) He also has quite an assortment of 6mm bolts, so a replacement should not be a problem. Lesson learned...always prep old bolts for removal first. He also made a suggestion: unless you have a very high quality allen socket, use a little valve grinding compound in the opening to help the tool 'bite' a little better.

Sincere THANKS to everyone for their suggestions.
 

CobraRed

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The Astro W00T sale has the socket and hand tool versions of damaged allen head removal sizes.
http://tools.woot.com/plus/astro-pn...er+-+6147012&utm_medium=affiliate+-+home.woot

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ibjuan

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Oct 10, 2009
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Pounding a sacrificial cheapo socket over the allen bolt head and using a ratchet on that socket has worked very well for me. Obviously this works best where you have room to hit the socket onto the bolt but this method has saved in the past.
 

tbaggz

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Astro pneumatic makes a set of damaged hex remover.and its on woot.com right now.
 

durallymax

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We always try a turbo socket type first on torx or Allen heads that are stripped.

Such a stupid design for a fastener and the euro manufactures love them unfortunately.
Allen heads yes, torx heads no. Torx is my favorite style head along with torx plus and xzn.

I don't know everything, but have yet to strip a torx, torx plus or XZN unless I was being stupid.

The biggest issue I see people having with those and Allen is failing to clean the head out. The design flaw is that it collects debris which doesn't allow the drive tool to engage fully or properly.

The next issue is not paying attention/improper use. Basically not having the right tool and/or not having it fully engaged due to poor angle or other reasons.

The other issue is poor quality tools, especially with torx. Although with torx poor quality tools will often break.

I've still had enough Allen heads strip out but honestly a lot of them are due to not cleaning them or not paying attention. The design of the Allen head is inferior to the torx design. The torx will strip much less.
 
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slik560

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Bingo: "The next issue is not paying attention/improper use. Basically not having the right tool and/or not having it fully engaged due to poor angle or other reasons."

The first bolt came out reasonably easy, so I did not notice that the angle of attack on the second one was slightly off. As soon as the socket slipped, I knew what had happened.
 

n8n

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Allen heads yes, torx heads no. Torx is my favorite style head along with torx plus and xzn.

I don't know everything, but have yet to strip a torx, torx plus or XZN unless I was being stupid.

The biggest issue I see people having with those and Allen is failing to clean the head out. The design flaw is that it collects debris which doesn't allow the drive tool to engage fully or properly.

The next issue is not paying attention/improper use. Basically not having the right tool and/or not having it fully engaged due to poor angle or other reasons.

The other issue is poor quality tools, especially with torx. Although with torx poor quality tools will often break.

I've still had enough Allen heads strip out but honestly a lot of them are due to not cleaning them or not paying attention. The design of the Allen head is inferior to the torx design. The torx will strip much less.

I've stripped out XZNs before, but only when they reach "a certain age." And yes, cleaning with a pick and some Brakleen, as well as a few love taps with a BFH to make sure the bit is well seated, is required.
 

n8n

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Post script: found a friend locally with the right removal socket. Former MB mechanic. ;) He also has quite an assortment of 6mm bolts, so a replacement should not be a problem. Lesson learned...always prep old bolts for removal first. He also made a suggestion: unless you have a very high quality allen socket, use a little valve grinding compound in the opening to help the tool 'bite' a little better.

Sincere THANKS to everyone for their suggestions.

awesome. So was the "removal socket" a turbo socket type deal, or one of the ones posted farther down? enquiring minds want to know. (the latter is actually new to me, I hadn't seen those before this thread.)
 

Dust Devil

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That sounds scary to Dremel off the only part of the bolt you can grab onto

You might be able to Dremel a slot across the bolt head and use a hand impact driver to get it started

If you can get to it this is usually the best way. You just have to be sure to notch the head nice and straight and then use a tip that fits the slot perfectly.

From what it sounds like it is in a tight spot so getting a cutoff wheel or dremel in there may be an issue.
 

Dust Devil

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Post script: found a friend locally with the right removal socket. Former MB mechanic. ;) He also has quite an assortment of 6mm bolts, so a replacement should not be a problem. Lesson learned...always prep old bolts for removal first. He also made a suggestion: unless you have a very high quality allen socket, use a little valve grinding compound in the opening to help the tool 'bite' a little better.

Sincere THANKS to everyone for their suggestions.

Can we get a picture of the socket ?
 

Nickmm

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Jun 20, 2012
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Glad it turned out. I dropped in to point out the Astro woot sale as well, but a few people beat me. I would say heat is always the best way to go if it can be done safely. Key word safely. I've put the bottle away a few times because it was in an area that creeped me out.

I had a stuck JIC hose today with an 1 7/8 head. I had the wrench infront of me and my back to a wall and could put everything I had into the wrench, no joy. There was paint over the fitting, so I picked out the paint, sprayed in PB-like stuff, and hit the fitting with a hammer on all sides, and after a few minutes tried it, it popped right off. Sometimes you just have to be vigilant.

And I bought the Astro Allen extractors because the nightmare you've just lived through has happened to me more than once. Ussualy the irwin turbo sockets get me out of trouble. Usually.
 
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