Main drive pully came off?
Thread Starter
Racer
Joined: Feb 2009
Posts: 425
Likes: 0
From: Diamondhead Mississippi
Main drive pully came off?
Friday night I was accelerating onto the interstate and got into the upper rmp then shifted i noticed a very hard shaking/rattle. i pulled over into a gas station and popped the hood and noticed the harmonic balancer pulley (i know its internally balanced) was about half way off.. i had to get it towed to my shop where i found that some silver looking metal came out which looked to be the splines. i put in a new bolt with lots of red lock-tight and torqued it down to about no problem but now the pully is wobbling a considerable amount..
one what would cause the bolt to back out in the first place
two is the pulley suppose to wobble...
one what would cause the bolt to back out in the first place
two is the pulley suppose to wobble...
Le Mans Master
Joined: Dec 2004
Posts: 5,493
Likes: 809
From: West coast CA
Friday night I was accelerating onto the interstate and got into the upper rmp then shifted i noticed a very hard shaking/rattle. i pulled over into a gas station and popped the hood and noticed the harmonic balancer pulley (i know its internally balanced) was about half way off.. i had to get it towed to my shop where i found that some silver looking metal came out which looked to be the splines. i put in a new bolt with lots of red lock-tight and torqued it down to about no problem but now the pully is wobbling a considerable amount..
one what would cause the bolt to back out in the first place
two is the pulley suppose to wobble...
one what would cause the bolt to back out in the first place
two is the pulley suppose to wobble...
Yours, however, is done. The rubber in the pulley is shot, which is causing it to flop around, which is probably the reason the bolt backed off in the first place. The "silver-looking metal" is possibly from the pulley scraping the front cover (or worse).
You need a new pulley AND a new bolt, which is torqued to yield and should not be re-used. The job is a PITA. Especially now that the existing bolt is glued in place with red thread-locker.
Good luck.
Melting Slicks
Joined: Jul 2000
Posts: 2,651
Likes: 6
From: redlands,ca.-usa
Bulletin Number: 05-06-01-001B
2005 Chevrolet Corvette with 6.0L Engine (VIN U - RPO LS2)
Built Prior to VIN Breakpoint 55111039
Condition
Some customers may comment on the Check Gages Light or the Battery Voltage Low indicator coming on. Additionally, some customers may comment on the accessory drive belt either slipping or being missing.
Cause
The crankshaft balancer bolt may have become loose.
Correction
Install a new crankshaft balancer pulley, washer and a new balancer pulley bolt using the following procedure.
Parts Information
Part Number: 12557840
Bolt, Crankshaft Harmonic Balancer
Quantity: 1
Part Number: 12598247
Washer, Crankshaft Balancer
Quantity: 1
Part #: 12583637
Balancer, Crankshaft Harmonic
Quantity: 1
2005 Chevrolet Corvette with 6.0L Engine (VIN U - RPO LS2)
Built Prior to VIN Breakpoint 55111039
Condition
Some customers may comment on the Check Gages Light or the Battery Voltage Low indicator coming on. Additionally, some customers may comment on the accessory drive belt either slipping or being missing.
Cause
The crankshaft balancer bolt may have become loose.
Correction
Install a new crankshaft balancer pulley, washer and a new balancer pulley bolt using the following procedure.
Parts Information
Part Number: 12557840
Bolt, Crankshaft Harmonic Balancer
Quantity: 1
Part Number: 12598247
Washer, Crankshaft Balancer
Quantity: 1
Part #: 12583637
Balancer, Crankshaft Harmonic
Quantity: 1
Le Mans Master
Joined: Dec 2004
Posts: 5,493
Likes: 809
From: West coast CA
I assumed the original poster's C6 was an '09, but now I realize that was his join date. I thought that paint looked like DSOM and not AO...
If his VIN is before the breakpoint, the TSB should apply. But either way, he's going to need a new pulley.
If his VIN is before the breakpoint, the TSB should apply. But either way, he's going to need a new pulley.
Pro
Joined: Apr 2009
Posts: 581
Likes: 10
From: NJ
I have an 05 vin that is post the above technical bulletin and it wobbled a couple months back. Do yourself a fav and bring to a shop that deals with vettes, ecs for example, and have then pin the crank while in there to save you future hassle.
Thread Starter
Racer
Joined: Feb 2009
Posts: 425
Likes: 0
From: Diamondhead Mississippi
It isn't supposed to wobble very much. Some people claim to have pulleys with no observable run-out at idle, but it's common for them to wobble very slightly.
Yours, however, is done. The rubber in the pulley is shot, which is causing it to flop around, which is probably the reason the bolt backed off in the first place. The "silver-looking metal" is possibly from the pulley scraping the front cover (or worse).
You need a new pulley AND a new bolt, which is torqued to yield and should not be re-used. The job is a PITA. Especially now that the existing bolt is glued in place with red thread-locker.
Good luck.
Yours, however, is done. The rubber in the pulley is shot, which is causing it to flop around, which is probably the reason the bolt backed off in the first place. The "silver-looking metal" is possibly from the pulley scraping the front cover (or worse).
You need a new pulley AND a new bolt, which is torqued to yield and should not be re-used. The job is a PITA. Especially now that the existing bolt is glued in place with red thread-locker.
Good luck.
Le Mans Master
Joined: Dec 2005
Posts: 6,999
Likes: 1,685
From: Southeast TX
The balancer is made of a softer material and will usually take the damage without damaging the crank snout. Good luck
. If your future plans may include a supercharger, pin the crank now and don't go with the u/d pulley.
. If your future plans may include a supercharger, pin the crank now and don't go with the u/d pulley.
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