Serpentine belt will not stay on pulleys?

[DeadHammer]

OK, I know this sounds crazy but I could really use some help here. I replaced a squeaky serpentine belt last Friday drove to work back and all around town no problems and today I went for my morning Sunday drive, I merged on to the highway the belt "tracked" off the pulleys! The belt I installed was one of the Goodyear Gatorback belts, I've never run them before so I figured I'll just get the cheap-o belt (with out the fancy cross hatching across the inside, well the cheap-o normal belt popped off too! All I can say is WTF!? Any body have any ideas? Now this Jeep is a 98 Wrangler Sport with A/C and power steering and a 175,000 miles, It's not the first time I've replaced it's belt before (I worked for Autozone, Jiffy Lube, Grease Monkey and Midas I can do this basic stuff pretty quick) and have never come across this before. The top tank on the radiator does leak a little from the crimped seal at the core (think this is why I had to replace the belt in the first place) but I made sure there was no coolant on any of the pulleys before I installed the belt (they are all in what appears to be good shape, they all turn effortlessly and not bent), from standing on the driver side looking down into the engine bay it almost looks like the crank pulley sticks out a little farther then the rest of the pulleys, the belt size is 910K6, I've tried having the belt a little loose, Nada and then a little tighter but same thing happens. It slips off at the water pump as it feeds to the alternator when I bump the engine over. Any help would be much appreciated.:???:

 

[SteelHeadz]

Looking from the top of the engine, use the alternator as a reference and verify that all the pulleys line up. also make sure none of them are loose or wobbly. i dont recall you mentioning the type of engine you have, weather it has an automatic tensioner or a manual type. i would suspect either the waterpump or a tensioner pulley to be at fault. i could be wrong. either way your looking for a pulley that is tilted over enough to throw the belt off. good luck.

 

[DeadHammer]

Picture update, still having the same problem.

OK here are some pictures from my engine bay (fan shroud, fan and water pump pulley removed for clarity and I know the radiator needs replacement). As you can see the harmonic balancer / crank pulley is positioned much farther forward than any of the pulleys (about 1/2 an inch). Can this part work itself loose over time? And yes it does have a manual tensioner. The water pump shaft has zero play in it all off the pulleys are square and rotate freely. This is a 4.0 engine.

 

[LVRockCrawler]

looks like a problem i had w/my old 91 - check the harmonic balancer pulley (crank) - looks like its seperating (its a 2 pc. unit w/dampening material b/w the pulley and hub...)if its sticking out too far its probably the culprit.... - mine was just enuff to jump 1 groove and start shredding the belt... pictures speak a thousand words eh? that looks like the problem... g'luck and let us know..

 

[SteelHeadz]

I agree with Bob. the pulley to Damper bushing is worn out and slipped off enough to throw the belt off.

 

[DeadHammer]

Yup, you guys nailed it (thanks). And here some pics, I'm going to install the new one tomorrow.