Alternator Pulley Swap

[ktneifert09]

I have to change my alternator pulley from single to double to match my AC car.  I pulled the single pulley but am trying to figure out if there's a way to press on the new double one without going to a machine shop or something.  Any tips on this?

[John_Kunkel]

The alternator must be split in halves so the rear of the rotor can be supported while pressing on the pulley.

[Just 6T9 CHGR]

The alternator must be split in halves so the rear of the rotor can be supported while pressing on the pulley.

Thanks for the heads up John as Ill be doing this sway soon as well

[maxwellwedge]

Actually - you were lucky to get the single pulley off without mangling it while your alternator was still together.

[Just 6T9 CHGR]

I had no trouble getting the double pulley off when I finally used the right tool.  Screwed up the first pulley I had by trying to grab it under the pulley instead of using the righ puller that grabs it by the center hub.
As you know the "correct" double pulley had the hub that is recessed inside the pulley & does not stick out like a lot of the newer stuff does...

This is the puller I used




And the double pulley

[maxwellwedge]

I had no trouble getting the double pulley off when I finally used the right tool.  Screwed up the first pulley I had by trying to grab it under the pulley instead of using the righ puller that grabs it by the center hub.
As you know the "correct" double pulley had the hub that is recessed inside the pulley & does not stick out like a lot of the newer stuff does...

This is the puller I used




And the double pulley

I confess - I did the same on the "first" one. 

[Just 6T9 CHGR]

The dang thing "unfolded" like an accordion

[ktneifert09]

I used a puller like you show and the single pulley came right off.  The measurements show that the double pulley is an interference fit of about 0.001 with the shaft.  By my calculations, if I put the shaft in the freezer and put the pulley in the oven to 350, I should eliminate this interference and be able to get it on with just a little bit of force.  I'm going to give it a try - what the heck, worst case I buy a new alternator and with the money I'm putting into this car, that's the least of my worries.  I'm not even sure that the alternator I have works either so I might end up with a new one anyways.  I'll let you know how it goes.

[Just 6T9 CHGR]

Sounds like a plan...let us know if it works....will save time on disassembling

[ktneifert09]

Worked like a charm.  I put the shaft in the freezer for about 20  minutes, put the pulley in the oven at 350 and when I took them out, I barely had to hammer it on.  Certainly no harder than the bearing goes on inside the alternator. However, I don't know if the alternator works still - it may not have worked in the first place.  Unfortunately we are many weeks of body work before we can start the engine - too much welding to do to have fuel around.

[Just 6T9 CHGR]

Cool....did you just throw the whole alternator in the freezer?

[ktneifert09]

No, I took it apart as far as I could and then put the shaft and the armature in the freezer.  Didn't see anything there that could get really messed up.

[General_01]

My cousin put the March single groove pulley on by filling a coffee can with water and heating up the water with his torch in the garage. He dropped the pulley in and let it heat up for a while and then put it on the shaft. It went on the shaft a ways, but he still needed to heat up the pully a little with the torch on the backside of the pulley and a little tapping. Worked great, but he is used to doing things like this. He used to work as a deisel mechanic and then as a welder and machinist in a hydraulic shop.

By the way, the pulley still looks great. That's why he used the water. To much direct heat would probably have warped the pulley and/or ruined the finished look of the pulley.

[Just 6T9 CHGR]

I had my pulley powdercoated so I know it can withstand the 350º in the oven for a while.
Still have a while to do mine though