crank bolt is broken off
Thread Starter
Racer
Joined: Jul 2007
Posts: 462
Likes: 21
From: Kansas City Missouri
crank bolt is broken off
original thread http://forums.corvetteforum.com/c4-t...post1571472088
I went to check the cylinders today for damage from the blown head gasket issue that I had and we discovered that the bolt that holds the harmonic balancer on is broken off into the crank. There is only about 1/4 inch of threads showing. I am guessing it has been like this for about 10 years or so now.
How do I deal with this problem? Is it best just to pull the motor and try and drill it out, or am I looking at a new crank and all of that? If the answer is pull the motor and replace the crank, what else am I going to need to do while I am in there? Oil pump? Do I go back completely original? I know nothing about this (as usual) so any advice is welcomed.
Thanks
I went to check the cylinders today for damage from the blown head gasket issue that I had and we discovered that the bolt that holds the harmonic balancer on is broken off into the crank. There is only about 1/4 inch of threads showing. I am guessing it has been like this for about 10 years or so now.
How do I deal with this problem? Is it best just to pull the motor and try and drill it out, or am I looking at a new crank and all of that? If the answer is pull the motor and replace the crank, what else am I going to need to do while I am in there? Oil pump? Do I go back completely original? I know nothing about this (as usual) so any advice is welcomed.
Thanks
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Jake
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Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
If it doesn't come out easy, just use an Easy-Out.
You just drill a small hole in the crank, then put the Easy-Out in the hole your drilled, and trun it counter-clockwise. THe broken bolt "will" come out. You shouldn't need a new crank.
You just drill a small hole in the crank, then put the Easy-Out in the hole your drilled, and trun it counter-clockwise. THe broken bolt "will" come out. You shouldn't need a new crank.
Thread Starter
Racer
Joined: Jul 2007
Posts: 462
Likes: 21
From: Kansas City Missouri
Do you think that I will have to pull the motor to get to it? There is a small gap under the frame piece in the engine bay that I might be able to get in through. Any thoughts?
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
First I would soak the daylights out of the bolt with something like PB Blaster. Spray it on liberally and let it go for a day or two. Then do it again and let it set again. Maybe do it a third time.
With that 1/4" of stub and (assuming) good threads, put a nut on the stud and weld the inside of the nut to the bolt. Don't try to use Vise Grips before doing this as the fine threads of the crank bolt can get messed up very easily and then you won't be able to try the welded nut deal. If the PB Blaster has loosened up any rust or corrosion, you should be able to turn the welded nut and the bolt will come out.
With that 1/4" of stub and (assuming) good threads, put a nut on the stud and weld the inside of the nut to the bolt. Don't try to use Vise Grips before doing this as the fine threads of the crank bolt can get messed up very easily and then you won't be able to try the welded nut deal. If the PB Blaster has loosened up any rust or corrosion, you should be able to turn the welded nut and the bolt will come out.
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
I would remove the water pump pulley, and also the harmonic balancer, get a set of vice grips on it. Now you might have to either lock down the flywheel so the motor doesn’t turn, or you might be able to wedge the vice grips against the frame drivers side and bump the motor and use it's rotation to break the toque on the bolt. Welding on a nut would be best if you have the welder to do the job. Good Luck
Last edited by floridamale; Sep 12, 2009 at 08:11 PM.
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Thread Starter
Racer
Joined: Jul 2007
Posts: 462
Likes: 21
From: Kansas City Missouri
sorry....gave the wrong impression. This this is broken off inside the shaft. It is 1/4 inches inside the shaft. I dont' have a stub to work with. It is broken off 1/4 inch deep. I think the "easy out solution" is the only one, so the next question is whether I can get into that spot. It is super tight.
Last edited by Bensons86; Sep 12, 2009 at 08:37 PM.
Pro
Joined: Jun 2008
Posts: 610
Likes: 1
Left hand drill bits are worth a shot.
There's no doubt the remains of the bolt can be extracted. The question is whether or not it can be done in the car. When you're extracting a broken fastener the most important thing is to get the initial hole drilled on center and in line. If I were in your shoes I'd be looking at moving the radiator and a/c condenser out of the way to possibly get a straight shot at it from underneath. I don't know for a fact that you can, but it's a possibility worth investigating.
There's no doubt the remains of the bolt can be extracted. The question is whether or not it can be done in the car. When you're extracting a broken fastener the most important thing is to get the initial hole drilled on center and in line. If I were in your shoes I'd be looking at moving the radiator and a/c condenser out of the way to possibly get a straight shot at it from underneath. I don't know for a fact that you can, but it's a possibility worth investigating.
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
To get on the crank bolt properly means going between the PS rack (rack and pinion) and the tubing that supplies hydraulic fluid to the rack. If someone brought this problem to me, the rack would be coming out in an attempt to remove the bolt without pulling the engine.
Good Luck in removing the remnants of the crank bolt.
Good Luck in removing the remnants of the crank bolt.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
To get on the crank bolt properly means going between the PS rack (rack and pinion) and the tubing that supplies hydraulic fluid to the rack. If someone brought this problem to me, the rack would be coming out in an attempt to remove the bolt without pulling the engine.
Good Luck in removing the remnants of the crank bolt.
Good Luck in removing the remnants of the crank bolt.
maybe with the right drill extension ....
Le Mans Master
Joined: Feb 1999
Posts: 9,922
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Get a 90 degree hand held drill, use a left bit, smallest possible and cutting oil. It will be hard, unless you can get a good start. Use a good quality bit, carbide bit if you can.
I just went through this, and if I had listened to all this type of good advice, I would NOT HAVE HAD TO PULL THE FRICKIN' Engine to do it.
Let it soak, then take pulley and everything out of the way, and drill left with a good drill and drill bit and as long as you get a good start and can drill in a ways, a easy out will work after the fact. The 90 degree drill allowed me to go from the top.
Good Luck.
I just went through this, and if I had listened to all this type of good advice, I would NOT HAVE HAD TO PULL THE FRICKIN' Engine to do it.
Let it soak, then take pulley and everything out of the way, and drill left with a good drill and drill bit and as long as you get a good start and can drill in a ways, a easy out will work after the fact. The 90 degree drill allowed me to go from the top.
Good Luck.
Race Director
Joined: Nov 2003
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From: Overland Park Kansas
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So what causes a bolt to break off, yet be removable with an easy out? (Actually, this question applies to any broken bolt!)
And, to cover another question bound to be asked.... With the balancer still on the motor, is the only path to removal involve pulling the trans -- then the motor? (Seems like I read the motor [only] can't come out with the balancer still mounted -- because of the frame brace.)
And, to cover another question bound to be asked.... With the balancer still on the motor, is the only path to removal involve pulling the trans -- then the motor? (Seems like I read the motor [only] can't come out with the balancer still mounted -- because of the frame brace.)
Team Owner
Joined: Dec 2007
Posts: 20,974
Likes: 261
IMO soak it real good, then easy out it, if that fails, tac a nut on or have some one do it. if you soak it enough it should come out with an easy out.
I got a small real cheap 90 degree drill extension from harbor freight, you could fit that up in there for drilling.
I got a small real cheap 90 degree drill extension from harbor freight, you could fit that up in there for drilling.
Last edited by pologreen1; Sep 14, 2009 at 12:53 AM.
Le Mans Master
Joined: Feb 1999
Posts: 9,922
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
So what causes a bolt to break off, yet be removable with an easy out? (Actually, this question applies to any broken bolt!)
And, to cover another question bound to be asked.... With the balancer still on the motor, is the only path to removal involve pulling the trans -- then the motor? (Seems like I read the motor [only] can't come out with the balancer still mounted -- because of the frame brace.)
And, to cover another question bound to be asked.... With the balancer still on the motor, is the only path to removal involve pulling the trans -- then the motor? (Seems like I read the motor [only] can't come out with the balancer still mounted -- because of the frame brace.)
Pulling the motor is easy. Straight up without taking the hood off. I unbolt the transmission, then put a brace under the transmission as it will fall down. Then I unbolt everything holding the engine in, fuel line, engine mounts, exhaust, power steering etc. Really depends on L-98 or LTx type, but it takes a few hours by myself. Almost sailor proof.
Le Mans Master
Joined: Feb 1999
Posts: 9,922
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
So what causes a bolt to break off, yet be removable with an easy out? (Actually, this question applies to any broken bolt!)
And, to cover another question bound to be asked.... With the balancer still on the motor, is the only path to removal involve pulling the trans -- then the motor? (Seems like I read the motor [only] can't come out with the balancer still mounted -- because of the frame brace.)
And, to cover another question bound to be asked.... With the balancer still on the motor, is the only path to removal involve pulling the trans -- then the motor? (Seems like I read the motor [only] can't come out with the balancer still mounted -- because of the frame brace.)
Pulling the motor is easy. Straight up without taking the hood off. I unbolt the transmission, then put a brace under the transmission as it will fall down. Then I unbolt everything holding the engine in, fuel line, engine mounts, exhaust, power steering etc. Really depends on L-98 or LTx type, but it takes a few hours by myself. Almost sailor proof.
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
If you can just drill a pilot hole, then put a very strong bolt in the hole and weld around it. as soon as the weld is done the heat from doing it should make the broken bolt come out with ease.