quote:

---

Originally posted by boomski

If your at all proficient with a mig welder I have a technique that I learned when I was younger and working at an exhaust shop, It amazes everyone Ive ever worked with since then (anyone not afraid of the welder converts to it afterward) and I owe the old-timer that taught it to me countless labor hours over it. Ive gotten out bolts any were from 1/4 to as big as 5/8 in diameter and even bolts broken off 1/2 inch deep.

Step 1
If it's deep you just do small tack welds on the top of the broken bolt till you get the weld built up out of the hole

Step 2
If level with the surface or after step one, place a washer the size of the broken stud\bolt on the surface (if its vertical you may have to hold it there with a pair of needle nose or the tip of a screwdriver until you get it tacked to your weld). Then tack the washer to the stud/bolt and after completely filling in the washer continue building up the center with tack welds

Step3
After the tack welds have been built up slightly in the center of the washer place a nut on top of this welded tit and then weld the center of the nut to that (you can also put small tack welds on three outside corners of the nut if you have problems with the nut wringing off in the last step).

Step 4
put a wrench or socket/wratchet on the nut and do small back and forth twist until it starts to come free

The heat from the mig welding tends to loosen up the bond between the broken fastener and the head (most helpfull on exhaust fasteners)and is usually enough heat however, in a few (very few) cases you may need to use a torch to heat the surounding metal slightly (and very carefully where gasket surfaces are present). The weld will usually come off the bolt one or two times before you get the fastener out, you just repeat the prosses. Ive had guys drill on bolts break off the extractor in the fastener you name it, and eat up the better part of a day to boot. Ill tell them to roll the welder down to the bus while I go get the nuts and washers from the parts room. Then finally revel in the dumbfounded look I get when the bolt is out 10/20 min later. Ive even been able to do this with a fair amount of interference (way tighter than you could have gotten into with even a 90 degree drill). I know most people cringe at the thought of welding the fastener into the head or really doing some damage to the hole but as long as you have the welder set right, aim strait, and do real short tack burst (real short) the weld wont have time to sufficiently heat and stick to the sides of the hole which is why the prosses will generally need to be repeated before the fastener is completely extracted.

I've used this method since I was in my teens and since learning it I have gotten 99% of all my broken fasteners like this and comonly teach other techs to do it this way, like I said before those who are not afraid of the welder.

---