964 Fan rub marks on the bottom of housing

[bazar01]

While checking on alternator and fan belts I noticed there were some rubbing marks on the bottom of the fan housing. I removed the A/C, fan and alternator belts. The fan spins free and not rubbing and has some clearance between the housing without belt tension. The fan bearing is tight and spins smooth with no noises on the alternator shaft. The alternator has a little up and down play on the shaft. Does this mean I have an alternator bearing going out or could this be the alternator bearing housing is worn? The alternator shaft spins smooth and quiet which makes me think the alternator bearing is good.

What are my chances that the alternator bearing housing is worn and loose? Is this a common alternator failure due to the fan and alternator belt loading?

[yelcab1]

Yup. That means the alt bearing is getting old.

[bazar01]

I am hoping it's just a tired bearing. Thanks for the encouragement.

I went ahead and pulled the fan/alternator housing assembly and separated the alternator. It appears that there is a slight radial play but not sure if it's a loose bearing or a worn shaft or a worn alternator bearing housing. I took it to an alternator shop for bearing replacement. The shop owner also mentioned that if it is a worn housing, he can fix that too.

There was not a lot of play but it was enough for the fan to make contact due to belt tension.

[bazar01]

Got the alternator back from the shop. Alternator rear bearing housing was worn and bearing moves a lot inside the housing. Sleeved the housing and changed both bearings for $50, installed new fan and alternator belts and I am back on the road today.