Alternator Pulley Removal - Advice Required

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powbongo

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I am trying to replace an 11mm wide alternator pulley with a 13mm pulley on a presolite alternator and I can't release the nut holding the original pulley on. There is a allen key slot in the spline that the pulley sits on and have held the allen key and placed what I consider to be a lot of pressure on the nut but the ba##&@d will not shift. I am mindfull of damageing the alternator which is new, any suggestions please would be gratefully accepted.
 
I believe it's an ordinary right-hand thread. Perhaps apply some heat (hot air gun) and try again? You're unlikely to damage the alternator.
 
Hold the pulley by wrapping an old belt around it and gripping the belt in a vice.
The nut may be loctited on. Try heating it with a hot air gun or heating an old/cheap socket over a gas flame.
Check it's not a left hand thread.
 
Had a similar problem recently - was advised by manufacturer easiest thing to do was take it to someone who has an air gun type that takes off wheel nuts (Kwik Fit ?) and get them to remove the nut.

They said to tell whoever was doing it to wind down the pressure on the gun as they should be able to lightly vice the pulley with a rag then apply intermittent pressure with the gun to "start" the nut.

In the event my yard had such a gun and the nut came off as sweet as - - - well - a nut.
 
Crowblack said:
Had a similar problem recently - was advised by manufacturer easiest thing to do was take it to someone who has an air gun type that takes off wheel nuts (Kwik Fit ?) and get them to remove the nut.

They said to tell whoever was doing it to wind down the pressure on the gun as they should be able to lightly vice the pulley with a rag then apply intermittent pressure with the gun to "start" the nut.

In the event my yard had such a gun and the nut came off as sweet as - - - well - a nut.
Click to expand...

Definitely - I've had to change a few alternators and swapping the pulley was a major problem - tried vise, everything. Airgun in a Spanish garage solved it. I had a compressor anyway, now I've bought an air gun and it works a treat.
 
powbongo said:
I am trying to replace an 11mm wide alternator pulley with a 13mm pulley on a presolite alternator and I can't release the nut holding the original pulley on. There is a allen key slot in the spline that the pulley sits on and have held the allen key and placed what I consider to be a lot of pressure on the nut but the ba##&@d will not shift. I am mindfull of damageing the alternator which is new, any suggestions please would be gratefully accepted.
Click to expand...

Dont understand the problem everyone seems to have with this. If you are going to discard the pulley that's on there then put the pulley in a vice and get a good size socket on the nut. It should come off relatively easily. I just fitted two new Prestolites and didn't have a problem. If you wan't to protect the pulley to use it again put an old belt around it and then in a vice. The allen screw is a help when putting the new one on but you will never get enough purchase on a standard allen key by hand. hold the key in a vice with just the end sticking out, shove the shaft on it and use an open ended spanner on the nut. Simples!
 
I know a previous poster says the thread is RH but most engines turn clockwise looking at the front. So the alternator turns clockwise. Wouldn't that imply a LH thread to prevent the nut undoing when the engine was running?
 
theoldsalt said:
I know a previous poster says the thread is RH but most engines turn clockwise looking at the front. So the alternator turns clockwise. Wouldn't that imply a LH thread to prevent the nut undoing when the engine was running?
Click to expand...
And the nut turns clockwise to tighten so a RH thread is correct - a LH thread would tend to slacken off.
Also why little effort is needed to tighten the nut but they are a bugger to get off later after several hours running.
 
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