broken bolt in block. need good advise

[froggy]

good luck you will get it im sure

[semocoachworks]

Whoever said kroll oil, kudos to you. Kroll oil here is 15 dollars a can but works wonders. You can get the reverse drill bits from any major tool supplier. the big 3 have the reverse bits with easy outs as a kit. They are a little spendy but I use straight flute machine bits to drill out broken, or tempered bolts. With these, you want to make sure your straight because you only get one shot. Center punch the broken bolt. On medium speed, kinda tap the bit lightly to chip at the center punch hole until you get it started. After getting into it deep enough for and easy out, use the kroll oil and let set for a while. It will come out using this method.

[chengny]

Grind the broken bolt flat and perfectly perpendicular to the C/L.

Next, as semocoachworks says, center punch the face (as closely as possible to the exact center). This is important.

Refer back to Hotrodpc's advice (#13) and drill a pilot hole using the smallest diameter bit you can (that won't break). Remember that the pilot hole and the first few step-ups do not have to be deep. They only act as guides as you begin to remove the interior of the bolt. And as he says "be sure not to drill too deeply as there may be an oil passage or cooling water jacket behind the bore". Or something to that effect.

Keep increasing the diameter of the bit (constantly cleaning the chips and cutting oil out as you do). Watch closely and you will eventually see the interface between the male threads of the bolt (which by now should be nothing more than a shell) and the tapped bore in the engine block.

Stop drilling and find, borrow, purchase a small round-nosed cold chisel. Take the tip, and working around the OD of the bolt, gently cave it in towards the drilled out center.

Now soak the threads with PB Blaster (or the penetrating oil of your choice - no joke - beeswax is extremely effective if you have access to some).

Apply as much heat as you feel comfortable with. Really try to come very close to a cherry red if you can.

Take a ratail file and use it like an easy-out. Being extrremely careful not to break it off or you will be worse off than ever.

[martinezm]

If you can not easy out those bolts, the only other thing to do is drill out the bolts using the correct tap drill size and re-treading the holes, be careful about going in to deep and use a bottoming tap. Good Luck. Regards Marty

[Chief250R]

Plenty of good info here, lots of luck......but if push comes to shove as a absolute last resort you can always take the block to a machine shop. It will be pricey, but time is money too.

[gmctrucks]

Here this should help. Maybe use a steel brush on the surface so some oil can seep in the threads.

Penetrating oil test.
Penetrating Oils Compared

Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts. Significant results!

*They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.*

*Penetrating oil ..... Average load*

None ..................... 516 pounds
WD-40 ............. 238 pounds
PB Blaster ............. 214 pounds
Liquid Wrench .. 127 pounds
Kano Kroil ............ 106 pounds
ATF-Acetone mix....53 pounds

*The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone*
*Note the "home brew" was better than any commercial product in this one particular test. A local machinist group mixed up a batch and all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.*

[83k10]

hey ya'll! sorry it took so long to reply, haven't had time to work on the 88 but i went down there today with a new set of heavy duty drill bits and some high grade cutting oil. got one of the bolts drilled out but when i was re-threading it, i broke the re-threader off inside >:O so next weekend i'm going to have to find a way to get that ****** out.can't do it tomorrow because its the super bowl!

[vansdonk]

Are you muscle f'n stuff or what. Hopefully the tap won't be as hard to get out. Usually they are made of a stronger metal then what you would use them on. Mini wire bushes could have helped clean obstrusions of threads before tapping.

GOOD LUCK!!!!!

[hotrodpc]

That's a fact. One thing I did learn working on vehicles. Broken bolts, re tapping, extractions etc, must be done with extreme patience. Must be done very slowly and lightly or just adds more time and more headache. If I am frustrated when doing that part of the work, I'll walk off do something else, and go back at it, when I am chilled out.

[Stitz Love]

I may be late with this, I read through the 3 pages, did not see this suggestion... I did see you got 1 out. (but broke re-threader off inside)

I had a bolt which was BENT then boken off in a motorcylce frame. (my last motorcycle)
I tried everything you have... here is what worked. (and I didn't believe it would.)
I used a dremmel to cut a slot across the top of the flush bolt. (Like a big Standard screw driver) when I was satisfied it was a deep enough gash to offer the flathead screw driver some purchase, I put the screw driver to it, and slow and steady began to turn it. It worked! I probably have photos of it I was so impressed. I'm also sure that two days of penetrating oils on it helped... but this bolt was bent as well as broken off. (I was rear-ended while stopped for a schoolbus on my way home from work. I rebuilt the Bike and sold it.)

Well there is my .02 hope it helps.