Idler pully wobbling front to back on shaft

[barrys]

I heard a wierd almost whistling sound in the engine. It's either coming from the top idler pully or the alternator (both original w/ 127K).
The idler pully was also moving back and forth on it's shaft with range of about 3/16" a little more than once per second.

Replacing the idler pully seems easy enough. But, I'm wondering if there's something funky going on with the shaft it sits on or some space plate or something on that shaft. I cannot seem to find any pics of it on the web after countless google searches.

Would movement like that on the pully shaft happen because of a bad idler pully? It doesn't seem like the sign of a bad bearing. But, I'm not sure.

 

[Stewie]

I recently went away for a 13 day vacation. When I returned, and fired up my 2002 ranger it squealed like a banshee. I looked at possible causes and one of them was the top idler pulley. I gave it a shot of WD and it stopped for a second. It was wobbly as well. I went to my Ford dealer and picked up a new puuley. They consist of a "Bell" like outer shell with a bearing and a long bolt that goes into the block. Mine was 60 bucks with tax in Canada. Just release the belt tension and slip the belt off the Alternator.
One bolt in the center of the idler. When you get the bolt all the way out the outer edge of the pulley will be contacting the fan. Just put the two blades of the fan on either side of the pulley and slightly bend the fan towards the front of the truck. That will allow the end of the bolt to come out of the block, and upwards. Reverse this for installation. I found that even after the pulley was replaced it still had a squeal. I replaced the Belt with a Goodyear gator back and now it is quiet and smooth.
If you look at my thread in the heating and cooling forum under A/C pulley howling, I have the part numbers listed. I originally thought it was the AC pulley. I didn't look for an after market pulley. You may be able to get one cheaper.

 

[barrys]

Thanks Stewie.