Idler pulley fell off -- Need help

I was driving down the road the other day when my Jeep began to overheat (99 XJ 4.0 auto / AC / PS 4wd). I pulled over and raised the hood, expecting to see that my serpentine belt had snapped. To my surprise, I found that the serpentine belt was OK, but there was no tension on it. The idler/tensioner pulley had fallen off completely, taking with it the mounting bolt and any hub / bearing that may have been used to hold it in place.

The local auto parts store hasn't been able to help me much so far. I searched AlldataDIY, but I haven't found an exploded view diagram to show what mounting hub / bearing / bolt I need to put a new idler on. The only thing worthwhile I was able to get from Alldata was a part number for the idler -- 4792112. Can anybody help me figure out what else I need? If anybody has access to P/N's, that would be great.

Thanks

A new idler pulley from your local parts place will have the bearing installed in it already.

I had a pulley seize on me and ride on the bolt for a while until it spun the bolt out of the bracket. IIRC that bolt was an M10.

Edit: M10-1.50 x 40 mm on that bolt. The original is a 35mm, but the parts places will only have a 30 or a 40.

My original thread here:

http://www.naxja.org/forum/showthread.php?t=900320

Erm, which idler? There are two - the one the fan rides on, and the one near the thermostat (that nothing rides on - it's there to change the direction of the belt's run.)

If you lost the upper idler, make sure you haven't lost the threads in the housing - if you have, a HeliCoil or a ReCoil will see to that (but you'll have to remove the bracket to install that - it's the entire aircon bracket that the compressor is mounted on.)

It's the idler that mounts to the power steering pump bracket and is used to adjust the tension on the serpentine belt.

5-90 said:

Erm, which idler? There are two - the one the fan rides on, and the one near the thermostat (that nothing rides on - it's there to change the direction of the belt's run.)

Click to expand...

OK - later model, then. Still - check to make sure the threads haven't pulled out before you replace the thing.

All you new fangled 97+ owners

RedHeep -- was yours the same pulley? Just wondering if your bolt measurements would be the same for mine or not.

My '91 has the idler pulley over by the a/c compressor. The belt tension is adjusted by adjusting the power steering pump.