Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUESTION!
 

what now? pull engine and have a excuse to build? Anyone have a easy fix? or am I just stuck with pulling the engine and taking it apart? stock z6 engine btw...

Before you tell me how much of a moron I am and how could I do such a thing.. I just bought the car less than 3 months ago..

I was racing it 50 minutes previous, was casually driving home... All of a sudden the battery light blinks a few times then comes on.. I hear a small rattling instantly followed by a huge bang as I ran it over.. I tripped the hell out for a second but kept it going like a trooper.

let me know your thoughts. if your going to tell me how cool I am for driving without a care in the world after it happened.. I know ;)

Re: Crank pully broke off, left half broken bolt...
 

well in reality to get the crank pulley off your going to need to cut the puley of. Get a powerful welder to weld a new end to the crank. Crank will be junk after welding most likely but you still have the rest of the block



In reality your going to have to bring this to a machinst has I doubt you have a tig

Re: Crank pully broke off, left half broken bolt...
 

get a pic, I don undersatand wit you said the pully did.
is it fell off or u broke the bolyt off?

Re: Crank pully broke off, left half broken bolt...
 

im guessing the threaded part is still in the crank? there usually isnt any tension on the threads once the head of the bolt is broken loose... just twist it out....

Re: Crank pully broke off, left half broken bolt...
 

drill into it, thread a nwe bolt into hole the, welt bolt to bolt and undo

Re: Crank pully broke off, left half broken bolt...
 

Yes. I can feel the bolt in there as I can only insert about a half a inch of my finger into it. Dont have a welder as you guessed Chris. Think possibly I can drill/tap and undo it that way? Or is welding absolutely nessesary? Now that I think about it how far its in there I dont think weldings a option unless I want to warp something down there. I will take a pic tomorrow but its pretty much as described as quoted.

Re: Crank pully broke off, left half broken bolt...
 

No way a bolt like a crank pulley yu will be able to drill and use an easy out. Hell a 12mm bolt sometimes wont come out a 17mm crank pulley bolt is stuck for sure



Honestly your best bet is cut the pulley off with an angle grinder. Pull the crank out. Replace with another used crank

Re: Crank pully broke off, left half broken bolt...
 

just drill a little whole and use a ------- easyout

Re: Crank pully broke off, left half broken bolt...
 

i dont know about the easy out. the crank bolt is a bitch under normal conditions. you said you heard something wrong in the block right. i would get a new crank and jack the car up and drop the oil pan and go to work.

Re: Crank pully broke off, left half broken bolt...
 

trans has to come off to do a crank...not worth doing it in the car imho since youd be working upside down

Re: Crank pully broke off, left half broken bolt...
 

word you have the oil pump on one side and the seal on the other. Out of the car for sure. My best bet is pull motor


angle grinder and get the pulley off



take crank to machine shop



No way imo is that bolt coming off with basic hand tools

Re: Crank pully broke off, left half broken bolt...
 

the fact that the pulley is gone tho takes all the tension off the threads of the bolt that normally hold it in, i would at least try a small LEFT hand drill bit and then an easy out, with no tension on the bolt it just may come out, its at least worth the 15$ and 20 minutes itll take you to try cuz it could save u big

Re: Crank pully broke off, left half broken bolt...
 

if you take the crank to certian machine shops or you might have to send it in, but there are machines out there that can "burn" a broken off bolt out of a hole perfectly without dammaging the crank's threads. I had to do this to a supercharger shaft it cost me about $12 to get the bolt burnt out much better than a $200 shaft. Not exactly sure what the machine is called my machine shop sent it out to another place to have it done.

I think he is trying to say the pulley already came off, thats what the loud clunk was. I would know it happened to me, but the whole bolt came out so I guess I got lucky.

Re: Crank pully broke off, left half broken bolt...
 

ill tell you how to fix this because it happened to me before..

ill admit, i forgot to put the keyway in the crank one time and just tightened up the pulley bolt to hold the pulley on. Went down the road and heard all kinds of clanging. I eventually found the pulley and the alt and power steering belts as well. Hopefully the bolt didnt just snap flush, meaning when you look at it head on its flat. This is rare, the remaining metal is most likely broken in there with some kind of a raised area and lowered area. As turbohf said, once the head of the bolt is sheared off, theres no tension holding those threads in the hole. Get out a torch and heat the crank evenly around the broken bolt inside, then using a sharp centerpunch and a hammer- tap at the raised portion close to the edge of the threads around in a circle to unthread it. Ill see if i can make a little drawling for you.

The easy out may work, but i think thats a grade8 bolt. Their no fun to drill through

Re: Crank pully broke off, left half broken bolt...
 

Thanks for everyones info. I will be getting to this in the next week. Will post up the madness when it happens!

Re: Crank pully broke off, left half broken bolt...
 

snap-on makes a set of extractors that use left handed drill bits, ive used them to fix a similiar situation for a friend

Re: Crank pully broke off, left half broken bolt...
 

Alright so I was just about to extract the bolt and my friend Oscar notices the nice chip where the key goes. Could this have been the failing point of the crank pully? I have another key and crank pully but I dont want to throw it on for the fact that it could mess up again. Suggestions please. Should I do it like that? I would normally just pull the motor and build it but budget is close to 0.

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Re: Crank pully broke off, left half broken bolt... UPDATE!! PIC!!!
 

I'm going to go ahead and guess that chip isn't a big deal. Getting that threaded section out is. Try drilling 2 small holes that sort of form a notch and try a flathead screwdriver or easy outs or drill and retap.

Re: Crank pully broke off, left half broken bolt... UPDATE!! PIC!!!
 

take a center punch and make a a dimple. take a small drill bit and drill about 3/4" to 1" in. work your way up to a big enough drill bit to get a good size ez out in. had this happen to plenty of b7's. get yourself another pulley cuz yours is probably not round anymore where the crank goes. put RED locktite on the other bolt. and your done. i havent had a problem and have also done it to plenty of customer cars.

Re: Crank pully broke off, left half broken bolt... UPDATE!! PIC!!!
 

Bolt Came out!! For those of you who guessed that there would not be any more tension on the bolt, you were correct! Came off pretty simply. Took the drill, make a small hole, used the bolt extractor and it came right off thanks to b20accord.

Alright the next issue at hand. The Chip where the key goes. Like I said above I am leaning to that was the part that failed and not the bolt. I believe it broke at that point then dominoed effect to the bolt. So I want to make sure that pully isnt going to fall off. b20accord is going to weld a lip on it but first we wanted to see if the metals will (bond) if thats the right way of saying it. Like if we can weld the pully on to the crank where the lip is. Thats all I wanna know if they are weldable. Let me know please. Nig Nog Garage baby.

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Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUESTION!
 

I wouldnt worry to much about that chip in the crank, Just stick a new key in there along with a new pulley if you'rs is f-ed up.

Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUESTION!
 

basically the key way is thrashed even more then the pics look like. And we want to know what everyone thinks of just ------- welding that damn crank pulley to the crank itself?? The crank is obviously garbage and he plans on tearing it apart in the future to build it, then we will just replace the crank anyways. This is his daily driver and we dont want that ---- to break again until he ripps the engine out so what u guys think about it.

Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUESTION!
 

hell yes you can. O0

Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUEST
 

the crank is trash. With a good bit of material taken out of it, its no longer in balance. If its his daily, and you want to do things on the cheap, i'd recommend using a square file to get that keyway in some condition where you can put a woodruff key in there, even if its loose. Then grab a new pulley and dont rev it too high

Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUEST
 

I'd run it. With the amount of torque on that bolt the pulley isnt going anywhere as long as it is torqued properly. And whats the worst that would happen? Youll be suck where you are now.

Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUESTION!
 

My crank pulley bolt loosened up on me and fell off along with the whole pulley one time at a stoplight. that sucked it really pissed me off, scrambling across the intersection looking for the bolt. just stuck it back on with a half assed busted up key, tightened it finger tight right there in the road and drove it home :1

Re: Crank pully broke off, left half broken bolt UPDATE,PICS!, FIXED! NEW QUEST
 

stupid ---- like this only happens to fat kids 8)