E46Fanatics - View Single Post - DISA stripped bolt
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Old 11-14-2012, 02:41 PM   #40
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Join Date: Jul 2012
Location: Liverpool
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Originally Posted by RayPooley View Post
Ok. First of all stop what you are doing and leave it until you have a plan. The DISA is plastic and if you slip and cut a hole in it you may be knackered.
What do we know?

This screw is an 18 mm long screw with a knackered head. Now I don't know who last put it back in place but, being a screw, I would imagine not a lot of torque was used in putting it back. Not a lot is required. So what we are talking about is getting some kind of purchase on what's left of the head (maybe you should talk to a dentist. They are good at this sort of thing. ) Joke. I'll be back in a minute or two.
Ok. I'm back.

What you need is a center punch (on the left) and a 3mm screw extractor, in the middle. That's its family on the right. You also need a 2mm metal drill ie: for drilling metal not wood. I haven't got one but you know what it looks like.

Here's what you do. You take the punch, which is hardened steel, and place the pointy end in the MIDDLE of the head. You then tap the punch firmly a few times with a hammer until it has left a significant dent in the head of the screw. About 2mm diameter. This dent is going to stop the 2mm drill from skidding when you first start to drill a hole in the screw. Ok? Its like a pilot dent. This is the important bit. Ideally you want to drill down teh center of the screw. That's the objective. You don't want to knacker the threads/hole in the manifold. So be ultra careful.

Once you have a satisfactory pilot dent, put your drill into your dremel, position the tip of the drill in the pilot hole and start drilling. MAKE SURE YOU KEEP THE DRILL IN LINE WITH THE AXIS OF THE SCREW. Be patient. Baby steps. Take your time. Drill about 5mm in, withdraw the drill until it is almost out (to remove swarf from teh flutes) and go back in again. Do this until you have drilled to a depth of about 10mm.

This is where the screw extractor comes into play. The screw extractor is a case hardened tool. The tapered bit on the end has a LEFT HANDED cutting thread. You insert this into your screw and start to screw it into the drilled hole as you would a left handed screw. ie: applying pressure and turning COUNTER CLOCKWISE. As the extractor penetrates the screw it will eventually get tighter and tighter until, instead of the extractor getting any tighter, the knackered screw will start to unscrew. Get it? Job done. But DO be patient. And put something in the engine bay so as to catch anything that you might drop. Always a good idea. Oh yeah. Get yourself a T40 torx bit.
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Last edited by RayPooley; 11-14-2012 at 02:50 PM.
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