Harmonic balancer bolt

It appears the bolt holding the harmonic balancer to the crankshaft is broken off inside the crank.

Looking for ideas on how to get it out!  

be sure to take out anything that limits your room to work...

like the radiator.. the engine cooling fan..    the belts and the crank pulley..  use cardboard to prevent damage to the radiator if you have enough room behind it to work..

in order to get it out.. if it is wedged in tight..

you have to center punch the exact middle...

get several 1/8" drill bits..  i use double ended 1/8" bits from automotive paint stores..

some better hardware stores will have a small selection of Left handed drill bits...    depending on the size of your broken off bolt..

i would start with the 1/8" drill *** drill it straight down the middle..  i have had to drill at an angle if the drill drifter off center when i started to get it back to the center.. then straighten the drill and continue...

when using the left hand  bits to back out snapped off fasteners... you drill the small hole about a quarter inch deep... then with the variable speed drill motor set on slow speed...   lean in hard... when you start drilling.. you want to bury the end of the drill into the metal..  this may turn out the broken piece...

if the bolt is broken off flush.. and you are a great welder.. you can weld a nut to the end of the broken bolt.. and back it out..   weld through the hole in the middle of the nut..   the heat from welding also expands the hole sometimes to let it back out easy..


if the bolt is corroded in.. bottomed out .. cross threaded..  you will probably have to drill all the way through the bolt...    use short pieces of copper tubing over the drill bit to limit the depth of the hold..

so stubborn broken fasteners..   you can also call tap extraction specialists...   you clear the way to get to it... they can burn the bolt out...   look in the business to business phone books...

it all depends upon how and why the fastener has failed.


when the bolt was tool long and was bottomed out in the hole..  those are in my opinion.. the hardest to remove..  those ... if you do it your self have to be drilled all the way through..  then on to the next size..  until you can back them out or pick out the pieces with a carbide scribe and a tiny hammer..


straight tapered easy outs also work...  and should be purchased with the drill sizes listed on them...

most cranks can be drilled and taped to the next thread size if the threads are damaged in the snout..  

Thanks..I've done what you describe before, but never in a place this hard to work, in such a critical part (the crank).  I need to take some measurements, but it appears to be broken off about 1/4" inside the crank nose.  

When I saw it, I just said "oh crap" and closed the hood!  

I got this car recently and was setting the points.  There's no window in this distributor, so I was going to put a wrench on the balancer bolt to turn it to the top of a lobe.  No bolt!

I'm weighing whether to try and do this with the engine in place, after removing the radiator, fan and shroud, or whether I should just pull the engine.  

what year and motor is it????


there are some small block chevys ... early ones.. possibly into the early 60's that were not drilled for a balancer bolt...

if you have the time... and the room to work around the car... take the motor out.. hang it on an engine stand...   be sure to mess around with the bolts  that hold it to the engine stand...    you might want to get some longer bolts and a bag of flat washers...    shim the bottom arms with washers to the engine sits totally level...   this will make it much easier to drill when the engine is on the stand... so you can drill it straight...   you might also want to put some long bolts into the front motor mount holes... so that you can get a good idea of the angle you are drilling at..

i do that when drilling and tapping.. really makes it easier to NOT MESS up...  

Hey waynep7122 I have an ezer way to do that. you might be interested in it.

Instead of taking the motor out. You can make a drill bit guide that blots to the front of the motor. just find center on crankshaft, line the bit guide up square with the crankshaft. And start drilling. just make the room to work around everything.

You can get what you need at a hardware store. round tube (with the id of the tube the same as the drill bit) and some angle iron. you can make it anyway you want as long as its straight.  

that's a great idea... but use a pipe flange...  with several bushing reducers and some short pipe nipples..

i just wonder if he has one of the undrilled cranks... i used to have one...  it's been 25 years.. but i seem to recall it was a small journal 327 crank...   the block it came out of did not have the front motor mount bolts drilled either.... i seem to recall that block had a suffix of MM....    it went in a package deal... when i had to change jobs..    i am almost sure it went to the scrap yard... as i stopped by the guys place who i sold the bunch of stuff to.. and it was no ware to be seen...   the stuff i had hauled home..  coated with krylon anti rust spray.. as it had to be stored outside... the scrap guys saw it one day..   came back and tossed it all over the fence...   i know they tossed it... as there were dents in the alley pavement...  

why not use a screw extractor ( E-Z OUT) they have always saved me!