How to remove the alternator rotor from the shaft?

[NobleHops]

Got a new/used rotor in hand but I need to separate my bad one from its shaft and it's being a bear. I see that the shaft is a bit conical and so I can tell which direction it needs to unscrew. So far I put a bit of oil down its threads and gave it a couple of hard taps with a hammer in the direction of removal to see if I could free it to unscrew. Then I clamped the center portion of the end of the shaft in my vice, taking care to avoid the end bearing surface and the threads, and attempted to screw it off - no joy.

What's the trick here men?

N.

[Larry Zimmer]

Hopefully, Dave will get in on this one, Nils. My thought is heat and an arbor press. I think it is a 'simple' press-fit on the taper. The nut pulls the shaft into the taper when assembling. With some sort of fixture, a 2 1/2 lbs. hammer might do it. The 'fixture' would be some sort of support behind the rotor not touching the shaft. I'd heat it overnight at about 250 in an oven first if possible. I've found that heat always helps to loosen things.

[Rick Pope]

I think Larry's right. It's a tapered press fit. Lay the rotor on a couple of boards so that it's supported, but the shaft is dropped between the boards. Now use your brass hammer to tap on the shaft. If you don't have a brass hammer, use something to soften the blow from a regular hammer. A piece of plastic or such.

[daves79x]

Yes, the rotor presses off the shaft. Set yourself up in a press is best, but the other methods suggested will work.

Dave

[NobleHops]

Thanks guys!

[Larry Zimmer]

I didn't think to mention, earlier, that the small end of the shaft is what fits into the bearing in the cover. DON't want to damage that! What you can do, is to back the nut off just enough so it is loose. Then, using an appropriately sized piece of steel pipe or deep-walled socket, press against the nut to loosen the shaft. It only has to move a 'hair' to become loose. If you can, install and tighten a second nut (assuming one can be found) against the first nut, after backing off the first nut. This will provide more bearing area on the threads when you push or hammer.

[NobleHops]

OK not be thick, so it is NOT threaded, just pressed into that taper with the torque of the nut, yes?

[daves79x]

Yes, just pressed-on. Sort of looks like threads, but that's not how it comes off.

Dave