How to remove alternator pulley screw?

[Boater On Thames]

I have purchased a new alternator to replace the faulty one. I found the pulley size not fit and the cooling fan direction opposite. So I want to replace it with the old one. The problem is that I can not even remove the new alternator central screw. Tried everything, every wrench, and I stand on the wrench and jump on it, but it just no movement at all. Any idea to remove it? Many thanks.

 

[Caraway]

Been there done that.
The only answer is an air wrench. Take it to a local small garage (or tyre fitter) and get them to put their air gun on it. It works.

 

[NorthUp]

When you say 'central screw' do you mean the nut on the shaft?
The hexagonal socket recess in the middle of the pulley is the alternator shaft, hold that with an allen key and slacken off the nut with a spanner.
Apologies if you know this, but no screws are involved in changing the pulley/ fan.

 

[DavidJ]

Again been there. The Allen key recess just stripped out.
Take the old alternator apart so that you can hold the armature in a vice the you can get some leverage on the nut.

 

[Boater On Thames]

Yes. I mean nut on the shaft. I used a hexagonal socket and a wrench on the nut. Tried very hard but no any movement. I think the strength I have used is way more than remove a tyre nut.

 

[Portofino]

Does anyone think it might be reverse threaded so it does not spin loose in function ?
So maybe if so try turning it to the right clockwise to undo it .

 

[penfold]

It will be well clagged with threadlock, waving a gas torch or a hot air gun at it for a few minutes will help.

 

[Poignard]

Does anyone think it might be reverse threaded so it does not spin loose in function ?
So maybe if so try turning it to the right clockwise to undo it .

Possible but unlikely as the pulley is probably keyed to the shaft.

16m52s

 

[Poignard]

See above

 

[DavidJ]

Yes. I mean nut on the shaft. I used a hexagonal socket and a wrench on the nut. Tried very hard but no any movement. I think the strength I have used is way more than remove a tyre nut.

Wow!
Caraways suggestion is the way to go then

 

[Plum]

Been there done that.
The only answer is an air wrench. Take it to a local small garage (or tyre fitter) and get them to put their air gun on it. It works.

+1 yes, that works. The airguns they use have a pulsing/hammer action that you can't replicate with a normal wrench. Take all the parts with you and get them to tighten back up.

www.solocoastalsailing.co.uk

 

[Caraway]

That's what I did with this one. I had struggled with it for a while and went round to the local small garage. It took (after finding the right size impact socket) about 4 seconds.

 

[volvopaul]

Yes. I mean nut on the shaft. I used a hexagonal socket and a wrench on the nut. Tried very hard but no any movement. I think the strength I have used is way more than remove a tyre nut.

Drill the nut to split it with a chisel

 

[Boater On Thames]

Thanks. I finally removed the nut myself. I used a bigger hexagonal socket through the mounting hold on the alternator body to stop the fan spinning. Put the alternator on the floor and one foot holding on it. Then used a socket on the nut, kick it by another foot many times. Job done!

Thanks

 

[rafiki_]

It needs an impact driver. As above, your local tyre dealer will have it sorted in seconds. Have done this a couple of times.