wilhelm

I broke one of the valve cover screws and I'm having trouble getting it out. I drilled and used a screw extractor but it broke off inside the screw. Since then I've been trying to drill a new hole for another screw extractor and I'm drilling into the old screw extractor without much success. I've spent a lot of time drilling but I'm not getting far. I've tried Crafstman cobalt, Dewalt cobalt, and Bosch titanium drills. Is there a better drill to use? What else might help me get a hole drilled?

flamingeye

You could try an epoxy glue. Degrease first, then glue onto the top off the broken bolt something that will be easy to turn. Off course be careful not to get any glue where you don't want it! Leave it to make sure it is fully cured, it still may of course just snap straight off depending how seized in it is.
I have had success with this method in the past. Good luck!
It will not be easy to drill into an extractor and you are in slight danger of tightenting it more by drilling and it 'grabbing'.

Granite 944

I feel your pain right about now. I AM no expert, but have had plenty of experience in the past with easy-outs/extractors to know ( I hate em....most the time), they must be used as a last resort type of option, especially when bolts/screws are going into the block (steel into allum., corrosion and heat cycle thing). At least the procedure for using them must be carefully thought out, and the "feel" must be carefully attended to (not always easy, huh).

Drilling hardened tool steel like taps/easy-outs/extractors is not easily done at all. Most of the time, you'll have to take the part to a EDM at a machine shop, and have them remove it.

I have used tap/reamer removal tools in order to reverse out the extractor/tap (only usefull if extractor is of the 3 or four flute type). I've taken a very small diamond shaped punch, and use it to drive the extractor in reverse direction to loosen it, or use punch to bust it up into little peices, so I can get it out of hole (WEAR SAFETY GLASSES!!!!).

The extractor can be drilled...... but..........you must use a very slow motor speed, use lots of lube with the cobalt or carbide tip drill bit, have plenty of the drills on hand, or resharpen as required, and if at all possible.......use left handed drills (yeah.......those are easy to find in a pinch..... huh).

Possible drilling out disasters...........running off center with the drill, destroying the hole in the block.....watch out big time for this! (can you say timesert?)

Using heat on the alluminum with a very tight bolt in it, before bolt breaks is always a much better bet, though, not always an available option till after breakage.

If you could post a closeup pic of this hole and its condition right at this time.......a few more options just might become available.

Disclaimer: I am no auto mechanic EXPERT.......just a weekend warrior, with lots of mechanical background.

Go slow and easy from here.......or it will even get worser..........Good Luck!!