Allen head bolt removal tips

Contributed by: Ray Calvo

If you have done any work on Porsches (and other German cars), you will notice that they are in love with Allen-headed bolts (and recently Torx-headed ones).  I don't know what the reason is for this, but I suspect it is ease of robotics assembly with them.

Biggest problem I have noticed with these bolts is that after they have been in place for several years, and you have to remove something that has been out in the elements, the heads are fairly easy to strip.  Not being careful about fully inserting the socket into the bolt, or cocking the socket as you apply torque will invariably strip them.  Once they are stripped, now you are left with how to remove a stripped bolt that's cold welded itself in place.

First, to avoid (or at least minimize the problem), DON't use an Allen wrench or socket that has a rounded, worn end.  Replace it, or you have a much higher chance of rounding the bolt head.  Sears will (still) exchange a worn/broken hand tool for a brand-new one.  As far as tools to use, would ONLY recommend high quality ones (Sears, Snappy, Snap-On, etc.)  Also, don't use an Allen wrench/socket with a worn end; replace it.

If you do strip the bolt, I have found two possible ways to get out the stripped bolt:


I have used the following emergency fix for several of the above situations, including CV joint bolts on two different 911s and a brake caliper bracket on my Audi.  This works for the smaller size Allen head bolts in my experience (up to approx. 8 mm hex).  Get a good quality 6" pipe wrench (mine is by Ridgid); this small size will allow you to get into relatively tight areas.  Wrap it around the bolt and pull up the slack.  Now, whack the end of the wrench with a good size hammer.  The wrench head will bite into the bolts and provide a good grip; the hammer will help shock the bolt loose.


I found this method when I stripped the 6 MM bolt heads holding the seat in place; these are buried inside a U-channel, and you only have access to about a 30 degree arc on the bolt head.  With a quality center punch and a heavy hammer, knock a centering kink in the center of the side of the bolt head (right angles to shaft, parallel to mounting surface).  Now, while holding the center punch in the indented hole, move the punch head to the right slightly so that the punch is at an angle to the bolt head.  Give the punch a sharp wrap with the hammer; if you're lucky, should be able to break the bolt free with a few tries.

On reassemble, recommend using a new bolt (even if you didn't strip the head) and coat
liberally with anti seize.

Much of the above should also be applicable to the newer Torx bolts.
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