Stripped Crank Allen Bolt

bryanmabbott

Well-known member
Joined
Jul 8, 2011
Location
Phoenix
TDI
'02 VW Golf Manual; '13 Touareg TDI
Back again fixing my brother's 06 Audi A3 with 154k miles. The water pump seal let go so we decided to replace the timing belt while we are it. First timing belt done by a VW mechanic at 115k miles including water pump. We successfully removed 5 of the 6 crank pulley bolts but the last one is stripped. It was semi stripped before we started Any suggestions? Bolt is 6mm Allen head

Things I have tried after I've soaked the bolts with PB Blaster numerous times:
1) 6mm hex punched in -- stripped it a bit more
2) T40 torx -- slightly small so stripped more
3) M8 triple square punched in -- made it round
4) Heat for a minute, then M8 punched in -- no dice
5) Bought Irwin Bolt extractors but no clearance between crank bolt and pulley bolt

Positive note, the timing belt on this car is an easy job. Much better than my ALH Golf and a heck of a lot easier than my notorius 2.7T Audi allroad.
 
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Franko6

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May 7, 2005
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Sw Missouri
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Jetta, 99, Silver`
Use a Torx bit. As you have already tried the 8mm, I can't specifically tell you what size, but large enough so that the teeth of the torx will form nicely in the bolt head. Torx will outperform any allen 10 to 1. I use this technique when removing stubborn allen head bolts for the harmonic balancer. Use a hand impact hammer, if you have it, with long enough extensions you can get a really good whack on the bolt.

To get the best bite on the stubborn bolt, heat it, hammer in the torx bit, then drill out the metal that is pushed forward by the torx bit and hammer in the torx again. It may also help to reinstall the other bolts, as the single bolt that is stuck may have less pressure on it by doing so.

In the most dire of situations, it may be necessary to drill out the head of the bolt. Match the size of the bolt shaft against a drill. The bolts aren't as hard as you may think.
 

dweisel

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Jul 28, 2006
Location
Wheeling, West Virginia
TDI
dweisel isn't diesel anymore!
I've had decent luck with hammering a socket over a stripped out bolt. Beating it on seems to help to loosen it. Choose a socket that doesn't quite fit over the bolt head.

Good luck,
dweisel
 

Tdijarhead

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Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Daughters car, 2005 Golf TDI Mine, all 5 spds
I've had decent luck with hammering a socket over a stripped out bolt. Beating it on seems to help to loosen it. Choose a socket that doesn't quite fit over the bolt head.

Good luck,
dweisel
A 12 point 3/4” socket works on those pesky wheel lock lugs when you lose the key. Get a 12 point junk socket of what ever size you need and put it on with a 3lb hammer then hit it with an impact gun if you have the room to get one on it.

I always use that same 3lb hammer before I ever start to remove those bolts. One or two smacks either directly or in conjunction with a piece of round stock usually lets them know it’s time to come out.
 

whitedog

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Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
The common thread on what everyone is saying is to hit the head of the bolt hard as this somehow loosens it. I have had 1/2 square drive plugs that wouldn't budge with a two foot breaker bar, but after a couple of good, hard square hits with a 3 lb hammer, they come loose with just the weight of the breaker bar.
 

maxmoo

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Jan 19, 2011
Location
Lakefield, Ontario, Canada
TDI
2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
Use a Torx bit. As you have already tried the 8mm, I can't specifically tell you what size, but large enough so that the teeth of the torx will form nicely in the bolt head. Torx will outperform any allen 10 to 1. I use this technique when removing stubborn allen head bolts for the harmonic balancer. Use a hand impact hammer, if you have it, with long enough extensions you can get a really good whack on the bolt.

To get the best bite on the stubborn bolt, heat it, hammer in the torx bit, then drill out the metal that is pushed forward by the torx bit and hammer in the torx again. It may also help to reinstall the other bolts, as the single bolt that is stuck may have less pressure on it by doing so.

In the most dire of situations, it may be necessary to drill out the head of the bolt. Match the size of the bolt shaft against a drill. The bolts aren't as hard as you may think.
^ Excellent advice! I concur about using a "hand impact hammer"also known as a "manual impact driver", it is a must have tool in situations like this. For those not sure what we mean check out this vid....
https://www.youtube.com/watch?v=wPjsBF98n7I

Thanks again Fanko6 for sharing from your wealth of experience! :)
 
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JETaah

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mi 48836
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96 B4V, 1999.5 jettaIV,2005 BEW Beetle
Hammering on a 12mm, 12 point socket works pretty good with those harmonic balancer bolts. (Thanks, Whitbread).

Also, when giving the heads a whack to crack the seizure, try hitting the head more from the side to scoot it laterally rather than straight on.
And, of course, there is torch power if you have it.... no need to go red hot with it.
 

diesel4ever

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Sep 2, 2004
Location
Ontario
TDI
Golf 2000, black
I have used larger drill bit to drill off the head of the bolt.
Once the pulley is off the bolt remnants come off by hand.
You will need a replacement bolt, though.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
I have used larger drill bit to drill off the head of the bolt.
Once the pulley is off the bolt remnants come off by hand.
You will need a replacement bolt, though.
Yes, remove the bolt head. I like the hammer impact, but I'm pretty sure there is no room.
 

Franko6

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May 7, 2005
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Sw Missouri
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Jetta, 99, Silver`
I use an extension that goes past the fender. On certain bolts, like the harmonic balancer bolts, I'd rather they had a triple-square of torx head, as they are so much more durable. Years ago, I beat some 6mm allen bolts that were for an ALH harmonic balancer into 45 torx bolts. I liked them so well, I put them back in.

Whitedog, I certainly agree with pounding on a bolt to loosen it. Really stuck allens, that is the first approach. I don't care if you call it a hand impact or manual impact hammer, they are an inexpensive and very effective tool. Whenever loosening a very tight bolt, the first step, if it will fit, is a hand impact and a 5-lb mallet. Beat the living hell out of it.

With the hand impact hammer, the chances of damaging the allen bolt is very minimal. As the impact hammer can be twisted in the direction you need to loosen, that is usually all you need. As my dad used to say, "Don't use force. Get a bigger hammer!" You aren't tapping these things to make them come out. You are beating them into submission.
 

oilhammer

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Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I assume this is the BPY engine?

Any way... air chisel. Works every time. I have become a master at it, LOL. Just get in there at the angle in which when you chisel on the outside edge, you are pushing it counter clockwise. And it will back right off. Never ran across one I could not get loose that way.
 

jokila

Vendor
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Dec 3, 2004
Location
Houston, Texas
TDI
2003 Jetta GLS, Manual
I almost always have problems getting one of these kinds of bolts off. However, I've never had problems removing these bolts on engines I have previously performed the timing belt work. I torque them to spec and always am able to get them off easy enough. I am of the opinion the ones that are hard to get off are due to gorilla mechanics not using torque wrenches. Maybe it's road crud causing it, but that doesn't explain my experience.
 

pdq import repair

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Nov 6, 2016
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idaho
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09 Jetta
I hate allen head bolts. My hatred stems more from the old CV joint bolts than crank pulleys, but yeah air chisel to the rescue if driving in a triple square fails.
 

UhOh

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Dec 24, 2014
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PNW
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2000 & 2003 Golf GLS
Are these any different than on an ALH? I believe that I had one stuck and ended up using a bolt extractor (worked great).
 

jokila

Vendor
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Location
Houston, Texas
TDI
2003 Jetta GLS, Manual
Are these any different than on an ALH? I believe that I had one stuck and ended up using a bolt extractor (worked great).
They are similar, but the OP says there is no room between it and the center crank bolt to use an extractor.
 

otm646

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Joined
Jun 20, 2007
Location
Metro Detroit
TDI
1998 AHU Jetta.
Look up the William Turbo extraction sockets. They're a little expensive but by far the best extraction sockets on the market. I use them industrially nearly every day. They're much thinner wall than the Irwin or Craftsman options.

Hammer it over the head and give it the beans. It's come right out.
 

vincej

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Jun 26, 2015
Location
Calgary
TDI
2014 Golf Wagon
I think the key here is that it was changed before. Someone else already got to it and maybe used high strength Loctite. The northland dealer here did the first few oil changes on my car and I get it back with one of the skid plate bolts broken off. They admitted they use Loctite, for whatever reason I don't know. Any offer to fix on their part? Not a chance.

If it has been put in with Loctite you may have to heat it to melt/burn it or drill and re-tap. I'd be careful with the heat though regarding surrounding stuff that could get damaged in the process.
 

bryanmabbott

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Joined
Jul 8, 2011
Location
Phoenix
TDI
'02 VW Golf Manual; '13 Touareg TDI
Finally was able to retrieve the bolt using a T45 torx bit and believe it or not valve grinding compound I've learned from a video from Eric the car guy. Thanks to everyone on this forum though. Appreciate all the responses and advice. I've bought the manual impact driver from Harbor Freight but it was a no go.
 

bryanmabbott

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Joined
Jul 8, 2011
Location
Phoenix
TDI
'02 VW Golf Manual; '13 Touareg TDI
And related, the bearing on the water pump pulley seized which my guess heated up the housing due to brown discoloration I see around the housing which then destroyed the rubber o-ring to flatten and leak coolant and to top it all off, the plastic impeller separated. Lucky brother, he caught it in time and the timing marks all line up.
 
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