How to separate fan and alternator?

amk · 02-22-2005, 10:47 PM

During a rally last November my alternator was failing so a local shop swapped in the fan and alternator from an old Carrera 3 engine they had sitting around.

I’ve since bought a brand new alternator to replace this second hand scavenged part, but my mechanic can not separate the fan from the alternator. He tried using a press/pull device and soaking it in stuff (can’t remember the name) to loosen it up. He’s worried that if he applies any more pressure he’ll break the fan.

Any suggestions?

Thanks in advance,
Andrew.

aj88cab · aj88cab's Garage

I used the "gravity method" described by others on the forum. It was very efffective. Drop the assembly from about 8-12 inches onto a couple of 2x4's and it just pops out. The alternator is already out in the pic, but you can get the idea.

This would be a good time to have the fan and shroud cleaned up and painted if you have the time. I had mine bead blasted and clear powder coated. For any painted finish, mask the fan blade edges and the alternator mounting surface to maintain clearances. Also make sure they pre-bake the parts if you are powder coating or it will bubble. Ask me how I know.

Before and after

Good luck
Andrew

Andras Nagy · 02-23-2005, 04:06 AM

You might also ask your powdercoater if he has "chrome" powdercoat paint. It is much more like the magnesium of the fan when new, and has less of the look of "paint" than Andrew's does. Not dissing Andrew's, just showing an alternative to the "painted" look.

alan911 · 02-23-2005, 11:36 AM

Easiest way is, make some threads in 2 of the small holes that go around the pully nut 180 degrees of each other with a 5mm tap.

Then thread 2- 5mm allen head cap screws into the holes and tighten them allternately a little at a time. The fan will come off smooth as silk.

The holes are just a smiggen smalller than 5mm so your not taking very much metal off and they're 180 degress apart so you're not going to throw anything out of ballance.

Beats gravity everytime.

When you put the fan back on, smear some anti-siez goop on the alternater shaft and the next time you can hand tighten the allen head screws and the fan willl slip right off or just wiggle it off.

5speed · 02-23-2005, 12:36 PM

amk - are you having problems removing the actual fan blades from the alternator or removing the alternator from the fan housing? Using gravity to remove the alternator from the housing is the method that I use. No chance of damage to the alternator mounting bolts.
I have never had a problem removing the fan blades from the alternator shaft, but alan911 method of tapping two of the holes sounds pretty good.

amk · 02-23-2005, 01:14 PM

Hi Guys,

It’s a problem removing the blades from the alternator.

Just talked to my mechanic and suggested the 5mm tap and screws (great idea), he’d already tried that, doh!

He was telling me he’s tried heated it for expansion and then put 10 ton on it with a press!!! Said he’s never seen anything like it. Sounds like it’s not coming off.

I guess we can keep applying pressure until either it comes off or it breaks...

Regards,
Andrew.

alan911 · 02-23-2005, 03:08 PM

Blades = Fan

10 TONS !!! HEATED !! and the magnesium, or whatever it made of, didn't shatter ??

Well, so much about the fan being fragile.

5speed · 02-23-2005, 03:42 PM

With all that pressure and heat it should have broke loose. As far as I know the only thing that holds the fan blades in place is the front nut and a woodruff key that keeps the fan rotating with the shaft. The only things I can think of is excessive rust on the shaft or maybe the woodruff key is cockeyed and jamming the blades from coming off.

amk · 02-24-2005, 04:47 PM

We’ve found another 11 blade fan in Melbourne which should arrive Monday so we can finish the car (this is the last bit of quite a lot of preparation work for the next rally).

I’m shipping the fan and alternator as one unit back to Mark (the guy we got it off in Adelaide). I’ve christened the alternator Excalibur. I’ll let you know if Mark has any success.

Regards,
Andrew.

Sonic dB · Sonic dB's Garage

Be careful with the fan housing...if its cracked...its toast. Also, go light on the powder coating....there really isnt that much room between the fan and the housing.

alan911 · 08-17-2005, 04:43 PM

Easiest way is, make some threads in 2 of the small holes that go around the pully nut 180 degrees of each other with a 5mm tap.

Then thread 2- 5mm allen head cap screws into the holes and tighten them allternately a little at a time. The fan will come off smooth as silk.

The holes are just a smiggen smalller than 5mm so your not taking very much metal off and they're 180 degress apart so you're not going to throw anything out of ballance.

Beats gravity everytime.

When you put the fan back on, smear some anti-siez goop on the alternater shaft and the next time you can hand tighten the allen head screws and the fan willl slip right off or just wiggle it off.