Whats the best option for removing alternator pulleys?

I am using a small Focus alternator but I cant find a belt the right length and have on the garage floor a Mondeo unit with a bigger pulley that I would like to swap over.

How do I 'lock' the pulley to undo the big nut in the middle??

Thanks,
Steve

Don't forget swapping the pulley size will affect the charge ratio.

as for getting it off I'm not really sure on the fords

Couple of options

1) air ratchet
The sudden spinning force of the ratchet (and the inertia of the alternator) can be enough to "crack" off the central nut even without clamping the pulley

2) stick a screwdriver or similar wrecking device up through a rear ventilation hole and through the alternator (obviously between the poles ) and if you're lucky and you've got a long enough screwdriver through one of the vent holes in front. Then use a breaker bar or air ratchet on the nut again...

If you're scrapping the alternator pulley then you can just try clamping it in a vice. If it still slips then grind flat survaces on the edge of the pulley (cover up the alternator vent holes first else if the pulley is ferrous you'll get a crunky alternator due to the swarf being attracted to the magnets).

Another option is to put some water pump pliers around the pulley, clamp the handles in the vice so the vice is squeezing the grips shut and then go at it with a breaker bar.

Using an old fan belt round the pulley and pinching the belt in the vice so it grips the pulley sometimes works.

Cheers

mark

As Per Mark, use an old belt in the manner of the strap type filter wrenches, unless you're scrapping the unit I wouldn't poke a screwdriver in there.

P.S. which focus is your alt from? the one that came with my 1.8 Focus motor was kin huge....
Cheers.
Pete.

Most these days have a hex for an allen key in the middle of the fitting.

Focus alt is off a 1.8, it is smaller than the Mondeo one. I don't want to damage either one, just want to swap the pulley.

Both have a hex hole in the shaft but obviously the socket covers it up. I tried holding the socket in my vice with an allen key through it but with the weight on the alt and the tightness off the nut couldn't get it off.

This is where a hollow socket set

(like http://www.tooled-up.com/Product.asp?PID=125319&Referrer=Froogle )

is useful...

You could make a simple breaker bar from a length of tube with a ground down bit of metal bar (to the size of your socket set) welded onto the side of it with a hole drilled through it. Attach socket, pass allen key through hole in the ground down nugget. Voila....

If using an old belt doesn't work use a ring key & an allen key in the middle.
regds
Ian

quote:

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Originally posted by britishtrident
Most these days have a hex for an allen key in the middle of the fitting.

---

I use a socket welded to a bit of 6mm x 40mm x 200mm bar with a hole drilled for the allen key.


keyless pulleys have to be really tight + use Loctite.

This is what I have. Should be something similar in the UK.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40749

Mark

Decent air wrench would get it off in seconds

That's what cranked ring spanners are for,

Old belt round the pulley in the vice That got both off and was able to tighten it back up.

Thanks for all your help

Steve

Measure the length of the belt you need and go to halfords the number on the belt is the length. They do all manner of length belts.

I wrecked a perfectly good lexus V8 alternator last week by putting somting in the alternator when trying to release the locknut, we first tried with a holow key and a smaller one on the shaft, no luck the shaft was wrecked within a minut.
after half an hour trying to loosen it up
a mate reminded me of him having an air wrech, it took 3 seconds for the lock nut to get loose.

so unless you have air power, you'll have a nightmare getting it off.

grtz Thomas