Crankshaft pulley wobble. What to do?

**SiskMan** · 10-20-2014, 07:29 PM

Just noticed my belt was squeaking and looks to be the crank pulley wobbling. How serious is this? Can I drive the car without fear of destroying my crank bearings? I really don't want this thing to come off going down the highway and don't know when I can replace it/have it replaced

**tatertot91** · 10-20-2014, 08:29 PM

The fact that it's wobbling could mean it's coming out or damaged. I'd be getting a better look at it myself or having it looked at asap.

**0rion** · 10-20-2014, 09:41 PM

don't drive it......those pulleys can do some serious damage if/when they come off at speed. You'll need to pull that one off and see if there's been any thread damage and then put a new pulley on it with a new bolt. If you use a stock GM bolt it will have to be stretched. Personally I would go with an ARP bolt for $30 and torque to spec. I want to say it's 230 ft/lbs but it's been a while.

**SiskMan** · 10-21-2014, 07:42 PM

I got the bolt today from the dealership. What do you mean it needs to be stretched? How do I go about doing that? I have all the tools and parts to swap the pulley tomorrow. Also how do I stop the pulley from spinning when I break the bolt loose? I got a strap wrench but doubt that will be enough

***SMWS6TA*** · 10-22-2014, 09:18 AM

You can lock the flywheel with a lock kit or I used a long 3/8" drive extension and wedged it between the block and through the pulley. It wasn't pretty but it worked to get my ARP bolt on. ARP's are so much easier to install vs GM bolt.

**0rion** · 10-22-2014, 09:52 AM

keeping the crank from spinning depends on if you have stick car or auto....on a stick car you can just put the car in 4th gear and on an auto I dropped the starter and wedged a couple screwdrivers into the flywheel to keep it from turning.
As far as stretching the bolt you torque the old bolt down to 240 ft/lb to seat the pulley then pull that bolt out and run your new bolt in. Torque the new bolt to 37 ft/lb's then go another 140 degrees. You can buy an angle degree gauge or you can buy an ARP bolt and just torque it down to 230-240.

**98TransAmWs-6** · 10-22-2014, 01:07 PM

Originally Posted by 0rion

keeping the crank from spinning depends on if you have stick car or auto....on a stick car you can just put the car in 4th gear and on an auto I dropped the starter and wedged a couple screwdrivers into the flywheel to keep it from turning.
As far as stretching the bolt you torque the old bolt down to 240 ft/lb to seat the pulley then pull that bolt out and run your new bolt in. Torque the new bolt to 37 ft/lb's then go another 140 degrees. You can buy an angle degree gauge or you can buy an ARP bolt and just torque it down to 230-240.

This. If it were me I would just get the ARP bolt and torque it down to the 240 ft-lbs and call it a day.

**SiskMan** · 10-22-2014, 06:35 PM

My pulley had some wobble to it so I got a new one and a new bolt. I got the old one off no problem with a puller and locking the flywheel. I put the new pulley on and threaded the OLD bolt in by hand an few turns and gently started to tighten. It went on real smooth all the way to the end. Now im trying to install the new bolt. I got the old bolt loose enough to move a few turns backward, but now its stuck. Like really stuck. Doesn't want to go either way. When I tightened the pulley back on I used minimal pressure and the engine barely even turned. I don't see why this old bolt wont come out. I'm afraid that I will snap the bolt off with the pressure needed to loosen it. What should I do?

**35th-ANV-SS** · 10-22-2014, 06:52 PM

Don't you already have a thread started on this?

**98TransAmWs-6** · 10-22-2014, 08:03 PM

How many threads are visible? On mine I used an impact to back it out. I wonder if the bolt is cross threaded or there is just a bunch of gunk and it is stuck. You could try some pb blaster to try and loosen the bolt up.

**pajeff02** · 10-23-2014, 03:17 AM

Yikes. Like Will said, some PB Blaster can be used to lubricate the threads as it will wick into the hole. You can also also try working the bolt in and out a few times to see if it will loosen up before you go at it with an impact. The "jolts" from an air impact may be the only way to break it free -- start with low torque and ramp it up as needed. Another option is to load the blunt tip into an air chisel and allow it to hammer at the end of the bolt for a bit. This has worked for me on several occasions on various fasteners. You should get a thread chaser (not a tap) to clean out the hole once you get the bolt out. Good luck.

**0rion** · 10-23-2014, 04:33 AM

what are you options? My point being that bolt has to come out so don't be afraid of it. I'm wondering if that bolt/pulley being loose and wobbling didn't booger those threads up some? The fact you were able to run the bolt in a couple different times tells me that the threads weren't completely gone though. Like someone else said......might have some trash that was in that bolt hole caught in the threads now. Take everyone's advice here and soak that bolt in pb blaster overnight then have at it. Try going both ways with it. Like I say.......regardless of the outcome that bolt has to come out.

**SiskMan** · 10-23-2014, 07:20 PM

Thanks for all the replies. The previous owner actually used the ARP bolt. I just got the bolt from the dealership and installed a new pulley. It still wobbles a little...

**SiskMan** · 10-23-2014, 07:24 PM

I got it out. I just let it soak in PB overnight and then worked it back and forth a quarter turn for about 30 minutes. Then used a breaker bar and it came loose fairly easily. When I took the bolt out the last couple threads were destroyed. Cleaned up the crank threads by blasting it out with break cleaner, and shop air. Then threaded a bolt I had laying around in and out a few hundred times (it seemed) going slow and using PB blaster. This got most of the gunk out and cleaned up the crank threads. Then installed the new pulley. Still wobbles a little though...

**0rion** · 10-23-2014, 09:19 PM

I'd say something isn't right there....whether it be a bent pulley or you've lost a few threads and not getting proper clamping force. Did you torque it to 240 to seat the pulley all the way before doing your final passes?

**pajeff02** · 10-24-2014, 03:19 AM

Define "a little", please.

**SiskMan** · 10-24-2014, 04:41 PM

Just wobbles a little. Idk how to explain it. Maybe an eight of an inch? Its not a smooth spin by any means but its not crazy wobble shake that makes me worry about it falling off. That bolt is crazy tight

**pajeff02** · 10-24-2014, 06:17 PM

I honestly haven't looked closely at the balancer on our car -- does it have the elastomer ring like the old style balancers?

**98TransAmWs-6** · 10-25-2014, 04:49 AM

Originally Posted by SiskMan

Just wobbles a little. Idk how to explain it. Maybe an eight of an inch? Its not a smooth spin by any means but its not crazy wobble shake that makes me worry about it falling off. That bolt is crazy tight

It shouldn't wobble at all and the spin should be smooth. This makes me think that the threads in the crank are damaged or that it isn't torqued down enough.

**RONS98TA** · 10-25-2014, 05:50 AM

So old pulley and new pulley both had a wobble? Is it possible to have a crank that wasn't formed correctly from the factory? I have never seen a pulley wobble when properly tightened and torqued down. I think even an 1/8 of an inch is too much, and may cause the serp belt to jump off at sustained high rpm's.