I was driving home this evening when I heard the belt squeal and next heard and saw a pulley darting off across the street....

Engine stayed running, never stalled....

I pulled over and parked, ran across the street and retrieved my crankshaft pulley.....or part of it.

After an inspection by lighter, I saw that the pulley weld broke free.

I searched the fourms and have not seen anything related to replacing the pulley assembly.

Is this a driveway repair or something more serious than getting a new pulley assembly, serp belt, and bolting it up?

Thanks.

 

Well pics would be of great help here...
I depends on what all is wrong, it could be easy or it could be nasty...

 

Theyre a two piece design so they're known to separate, but I've never heard of it happening like that. I did mine in vehicle with the auto zone rental tool and it was a royal PITA but its doable. You'll need to remove the bumper. Most shops will say the engine needs to be removed.

 

I just did this about a month ago. Buy a new "Vibration Dampener" at your local Autozone. It will cost you $65. You will need a "crows foot" style puller to get the old one off. You don't have to pull the motor, bumper, radiator or any of that stuff. I did it right in my own garage and all I had to pull was my front skid plate....for obvious reasons. Depending on how badly the serpantine belt was damaged, you may want to buy a new belt. The "good" Good Year Gatorback belt will cost you $35 at Autozone. This job only took me a couple of hours. I hope this helps.

 

Mine has not come off all the way, but caused my belt to come off, almost as soon as I heard it contacting the blades of the fan. No probs with anything broken from the belt, but at first I just thought it was a belt, so when I went to put the new belt on, I noticed that the belt channel on the balancer did not line up with water pump, and the light bulb in my head determined that my balancer (dampener) had shifted out.

The Haynes repair manual doesn't give much detail on it, but I'm guessing from what you have posted, I can get beneath it, pull the old one with a puller, and put the new one on w/o pulling the radiator and shroud (which appear to both require removal after the fan). Am I right?

 

Yep I have done 2 and you hit it on the head. This happens a lot on the 4.0 with miles. I check mine all the time. They are not fun to change on the side of the road

 

How much more work is it to replace the front main seal while you're at it?

 

there a 2 piece design seperated by a rubber ring..I have seen them chucked from cars many times but mainly on cars at the drag strip.

 

I thought I'd add my 2 cents worth to this thread. I've been hearing a squeak under the hood for a couple of weeks, couldn't locate it, so I stopped by my neighborhood auto repair shop. They were covered up, he said bring it in early Monday morning and he'd take a look. Early Monday morning I started the Jeep, the squeak was worse and there was a new sound. Leaving it running, I popped the hood to look. The new noise was the crankcase pulley rubbing the fan blades. I could see the pulley running in and out on the shaft. Just then the belt jumped off the pulley. I cut the engine, went inside grabbed my Haynes manual, it was a little vague about the subject. So I looked on the forum and found this post, it was a great help. I just got back from a test drive and everything seems to be good.

So here's my 2 cents worth. Unless you want to remove the radiator and grill, the crowsfoot type pulley is not the best option. The big screw is too long to go between the radiator and the engine. My local autozone had a "Chrysler Harmonic Puller". It is much more compact, I was able to install the puller and remove the pulley by myself, but it would have been easier with an extra pair of hands. While you're out getting parts and tools, stop by the hardware store and buy a 2" long, 1/2 " fine thread bolt, it will be a big help in installing the new pulley/harmonic balancer. Once you've got the keyway aligned, the longer bolt will reach through the pulley far enough to engage the threads on the crankshaft. After you tighten the long bolt enough to push the pulley most of the way onto the shaft you can remove it and install the original bolt and finish torquing it down. All in all, it's not that difficult. And as an extra added bonus, when I was removing the fan and shroud, I found a mangled and partly melted magnetic key holder with a spare key to my Cherokee!

The only problem I encountered was drivebelt tensioning. Nobody knows anything about the tension gauge mentioned in the Haynes book. I tightened the belt enough that it doesn't slip, and I guess I'll take it by the repair shop and get them to check it.