Ok guys, I had my crankshaft pulley fly off the other day while i was driving because all the bolts got stripped and the center bolt broke off. I have a new balancer, and the old pulley, and got the old balancer off with A LOT of persuasion.

Now I can see that there is still most of the center bolt stuck in the crank, and I can't drill it out. Its in too weird a position and i have no way to put enough pressure on it to drill into it.

I tried getting the balancer on anyway by tapping with a rubber mallet but it would'nt go on. So what do i do? This car is my daily driver and I can't afford to have it down for very long.

When I tried drilling it out the drill bit broke into 3 pieces. ????????
HELP!! if by chance you feel like emailing me with an ingenious plan or suggestion, email me at tubatom@hotmail.com

Thanks in advance for any help you can give me.

Tom



86 iroc 305 TPI, 700r4, Completely stock, 91k original miles.

 

Damn man.. that's a really jacked up situation. I would get a big *** drill bit and just drill right in the center of what's left of the screw. Even if you screw up the threads in the crank you can rethread it with a heli coil kit. That should work but it will take a while. If nothing works... I wouldn't bolt it on without a bolt because the balancer will probably wobble its way off over time.

I'd say get a big (9/16s or so) drill bit and just drill a big hole right in the center of the screw. Then rethread it.

 

Like Blackend said, that bolt has to come out. Try using a right angle drill, you might be able to get at the bolt better. I think the bolt is hardened (grade 5 I think), so use a good drill bit.

 

Grade 5.. no, grade 8, "Metric 10.9"- that's a hard sunofabtch to get out.

I snapped mine while trying to use it to pull my harmonic balancer back onto the crank... my mechanic charged me $100 to weld the balancer to the crank. It worked, and has been holding for the past 3 years, but man, try to avoid that situation!!

How much of the center bolt is left? A mechanic might be able to weld a nut onto the end of the bolt, and remove the bolt with a regular socket. In my case, I snapped the bolt so there was only one thread protruding from the snout. The piece of the bolt I held in my shaking hand had stress marks all over the threads- but we have different situations. I majorly botched all the threads in the end of my crank- your bolt head just snapped because the pulley took it off. So that means the bolt should still unscrew easily. (Mine was wedged.)

If there's enough, you could try to carefully grind a slot in the remainder of the bolt, and use a large screwdriver on it. But welding a nut to it might be your best bet. Use AAA to tow the car, and slip the tow guy a $20 when he drops you off at the shop. Just tell him "it won't start and I don't know why"... (probably because you removed the rotor from the distributor).

 

TomP has the right idea. But one thing I'd like to add to that is when you get it to a shop, use heat around the bolt after a nut or bolt head has been welded to the remainder of the balancer bolt. Have them heat up the nose of the crank with an oxy-acetlyne torch to help loosen things up. Good luck

 

Thanks for all the input guys. TomP dpes jhave a good idea, but it won't work for me, as the bolt is broken off about 1/2" inside the hole. I cant get at it. ugh, i also don't have AAA. Darnit.
What is the hardest type of bit i can get that might make it easier to drill it out?

 

Yes it is a grade 8 bolt very hard. You will have to use i nitrided steel drill bit. Very expensive and you cant buy it from Pep Boys or Autozone, I am talking 50 bucks for the drill bit. Next you cant allow that bit to chatter at all. It is very hard but very brittle. If it chatters a couple of times you will probably brake it. I believe that the thread is a 7/16 fine thread. At the very least double check my numbers on the thread size. You could try a regular metal drill bit but it will probably very quickly get dulled. I would suggest pulling the radiator and the AC condeser and trying to get at the engine through there.
Good luck man.

 

$50 for one bit? For Real? Wow.

 

Check out these photos of my situation. I know they're blurry, its hard to hold the camera over my head and aim it at the right place. this is al from underneath the car incase you cant figure it out...

 

another shot

 

and another

 

drilling out is your best bet.

 

I have heard that a left handed drill bit might work. They are just drill bits that you run the drill in reverse so if it gets a hold of the bolt it might turn it out. Don't know what they are really called but you get the idea. Just a thought.

 

I've tried to use those before. I think they're called "easy-outs". They're ok for little jobs but for a bolt like that thats really torqued in there, all you'll end up doing is breaking off the bit in the bolt and when that'll make drilling it out an even bigger PITA. I had a cheap pressure fitting for a fuel pressure guage break off in the fuel rail when i was tightening it down. I tried to use an easy-out and it snapped. Ended up taking apart the whole TPI intake so i could swap another fuel rail in.

And the fuel pressure gauge still isn't mounted yet.

 

red firebird is right...easy outs break!!!

 

I'd the easiest way out of this is have some one spot weld it in a couple of spots just to hold it on there. I'd say deal with it the next time you take the engine out of the car. That's how I would do it... it looks like TOO Much of a pain in the ****.

 

Actually, no, they might be part of an easy-out kit, but you can buy them individually. http://www.eastwoodcompany.com sells them. I'm not sure if they're hard enough to drill a 10.9 grade bolt, but they -are- meant for this kind of situation, so, who knows? The problem is waiting for the shipping...

 

Once you find a way to get the bolt out DO NOT hammer the harmonic balancer on. Geez. You need a harmonic balancer installer that slowly pulls the balancer on. DO NOT use the crank threads for pulling the balancer on! Do not hammer on the balancer! Buy or rent the necessary tool.

Tim

 

that is exactly what i did

 

If you're spending $50 for a titanium/nitride coated drill, you're the one getting "drilled". They are available from most industrial suppliers for about a buck more than a standard high-speed steel bit. And it might not be hard enough anyway without coolant. Try a solid carbide drill, about $15.00 (nore for a left-hand twist).

A drill with a left-hand twist is also NOT an E-Z-out. That is a screw extractor designed to fit into a hole that has already been drilled.

You may need to use an angle drill to gain access without more disassembly. Heat may help, but really shouldn't matter since the bolt shouldn't be bottomed or cross-threaded, and really shouldn't have a lot of corrosion in that location. Penetrating oil, an angle drill, and patience should get it. Rear end pinion shaft lock bolts are far worse,so consider yourself fortunate.

While you're out getting the correct drill, pick up a piece of 7/16-20 threaded rod and a couple of nuts. Use that and a large 1/2" drive socket to pull the hub into place. Don't forget to pre-lube the crank seal before you intall the hub.

 

I snapped the one on my original 3.42/open/drum axle... I was just going to take the center section to replace my blown '84 gov-lock. I looked at the broken bolt, and went to a junkyard for a $100 axle instead. Maybe one day when I'm bored out of my skull I'll buy some dental picks and get that lock bolt out. Then I can haul that axle to the junkyard. Two axles in one backyard doesn't look too good

 

A good cobalt or titanium nitrided bit with penetrating oil as a lubricant will drill a hole in the bolt without too much problem.

Be sure to center punch the bolt and drill a pilot hole about 1/8" diameter ALL the way through the bolt.

Then use a 1/4" drill and open the hole up for an extractor, if it doesn't break free with a moderate amount of torque, then I would try either shrinking the bolt with cold spray (comes in a can from radio shack) or heating the crank. be carefull not to overheat it.

 

It sucks I know, I have been in your situation before. Same thing happened to me. I snapped that sucker off inside the nose of the crank.

To me the best way to fix this is to take the crank out.

Jack the engine up as high as it will go in the engine compartment with the dizzy cap removed, put blocks between the motor mounts and the engine motor mount brackets. Take the flexplate/converter bolts out. Remove the rod caps, oil pump, and main caps and that crank will come out with the flexplate still attached. I've done this twice now with the engine still in the car. It can be done and it is a pain, but defiantely alot easier rather than trying to dick around with the crank still in the car. OR you can just take the engine out all together. After getting the crank out take it to a machine and go from there.

Goodluck

 

Ugh.. And I was panicing when I stripped the bolt. I could get the bolt out, but only was able to catch some of the threads. I have a little torque on it - enough to keep the balancer from walking off - but I need to replace the bolt with a new one and apply the proper torque before I'll be able to sleep at night.

 

I saw a DeWalt 90* drill in the pawn shop today for $90...the
perfect drill for a problem such as yours. I would use a Dremel
to grind a divot in the center of the bolt and then drill an 1/8" hole about 1/4" deep then increase the size to 1/4" about 5/16"
deep and drive a good brand of T-45 TORX bit in it and unscrew it.
Use a harmonic balancer installer if you can. Put a bit of sealer around the inside of the balancer neck to prevent an oil leak and lube the seal lip.

 

In your case, you can rethread the crank snout. The OEM bolt is a 7/16-20. You can tap the blind hole in the snout with a 1/2-20 tap (standard size) without redrilling. Use a bottoming tap instead of a plug tap, and lubricate with kerosene or specialty tap fluid. Be careful to pick up the same thread as the original, and back off the tap frequently to clear the chips.

Install a 1/2-20 grade 8 bolt with your original washer, and torque to 65 ft/lb only (on a cast crank). You'll likely have to drill or ream up the washer slightly to accomodate the larger bolt, but it isn't that difficult.

There was a reason GM picked a 7/16-20 bolt thread for this hole, and you just found it. Just use an installer to pull the balancer into position, or you won't have many options for crank repair next time.

 

heres a thought, I have never tried it before on a large bolt like this but it might work, take a dremel with a cutting blade and cut a slot across the end of the bolt large enough for a BIG flat head screw driver (one with a square shaft) then use the screw driver with a adjustable wrench for leverage on the shaft and some penetrating oil and heat to try to unscrew the bolt, I have done this many times on smaller bolts with great success but never with a large bolt like this. but it worth a try.


GOOD LUCK

 

That would work if the bolt were accessible enough, but it sounds like it is recessed into the crank too far to do that. I have used that method before too and it works well. Even if the bolt is not free spinning. I just use a hand impact to get them started in those cases.

 

If those bolts are real hard, and drilling it out won't work. Try busting it up with a center punch and a hammer. This will take awhile, but I have done this before. Another idea is to try and turn it with the punch. Keep hitting it in a circular motion and see if it will come out. If you try the busting idea, make sure you put a rag around the snout so no chips fall in the pan.

 

Tizz - You still with us, or stuck under the front of the car? Did you get that summonabich outta there yet? We're all hoping you didn't have to drop the crank...

 

Sorry guys I went out of town to death valley and mojave desert on a geology field trip. It was great fun. I ended up having the car towed to a local garage because i just don't have the means or time to deal with it. i figured it would be as good a time as any to have it at the shop since i was out of town for 4 days. I appreciate all of your suggestions, and I really hope this never happens to you!!

 

hey for any of you guys who have stripped the bolt off, your going to have to rethread it anyway to put a helicoil in it, why bother, just drill out the washer and get a 1/2 bolt, save the money that helicoils cost they seem to think that they are made of gold or something, I stripped mine, stupid mistake using the harmonic bolt to reinstall the harmonic, but it had worked before, stripped the threads out. Ended up rethreading the crank, and getting a much longer bolt, threading it more than half way so I could thread it all the way in and use a nut and the big fat washer for the harmonic and installs in minutes, no problems.

 

this happened to a buddy of mine, but his cause was different, he had dual paxton superchargers mounted on the stock balancer bolt. BIG MISTAKE!!!

anyways, he drilled it out himself, used a titanium bit, and lots of berr, cause it took him a half hour to an hour to do it. Mainly becuase of the confined spaces on a 4th gen LT1. Used a helicoil kit, and it works like a champ now.... Fun times....

 

so spot weld will work on the harmonic balance

 

Not an excellent idea. Also this thread is old enough to buy **** and join the Army.

GD

 

Don't weld it.

Drill out the remains of the old one, Heli-Coil the crank to the original size (7/16" - 14), get a new bolt. It's a special part, has a big super thick washer captivated onto it, you can get one from Summit or your local speed shop. Probably not a regular parts store but maybe.

 

Yep , for all the other good reasons to not take the hackjob way out , the biggest reason is ol man Murphy himself .

You know Murphy , the guy who invented Murphy's law , , , just waitin to rise up and bite your butt when you try to take the skeevy way out ?

Weld it this week , and next week when Murphy rips the outer ring from the rubber don't say ya weren't warned

 

Somebody is going to buy that car and post here with a WTF thread.

 

My apologies: it was pointed out to me that the bolt is fine thread, not std thread, as mentioned acoupla decades ago in an earlier post. 7/16"-20. My old-timer's disease musta kicked in right then.

 

No......………………...just...……...no.

 

So did he get it out or WHAT!!?? LOL
should be a rule here, 3x and your out. If you post asking for help, get the help, but dont come back with results, your outta here!

I know, old enough to join the army. Lol