Is there something wrong with alternator?

[panelbilly]

I'm assembling the alternator in the fan housing and something isn't fitting properly. I set the fan as far down as I can and the shaft doesn't appear to be long enough. I haven't put the spacers (washers) on and the threaded section isn't wide enough to keep the final washer centered. I did have this alternator rebuilt. Could it be that the wrong shaft was installed?

[MikeD]

It looks ok to me in the first picture. Did you rotate the outer pulley half until the flats line up? The outer pulley sits entirely over the flats of the inner pulley.

[Walt Fricke]

Since I've not had issues, this isn't something I've thought through. But I recall that the cup washer centers itself on the wide boss (cut down on each side to hold the outer pulley half, same as the spare spacer shims fit, doesn't it?

When tightened, the cup washer is supposed to stand a bit proud of the protruding part of the fan. Sometimes, when guys omit to put the spare shims in there, they tighten the cup washer to the point where it bears on the alternator shaft without pressing hard enough on the outer pulley half. Even a little bit of looseness in this pulley half allows it to grind its way into the fan boss. Eventually it cuts a groove around the ends of the boss, and then the outer half can rotate relative to the fan. So a proper install leaves a space between the flat of the cup washer and anything under it, with all its pressure on the outer pulley half being around its protruding circumferential edge.

I don't remember there being all that space between the shaft and the ID of the cup washer, though. All my wrestling has been to keep the top shim or shims on the stack of spare shims in place around the truncated fan hub, so they all line up with the edges of the cup washer. The fan belt keeps trying to mess this alignment up until you get it pretty well cinched down.

Alternately, maybe you don't have the fan fully set. With some washers with a large enough ID you might be able to use the nut to draw things tighter? I wouldn't use the cup washer for this purpose, because, if you overtighten the nut on it, it will bow inward. I've got one or two of those in my parts bin.