Changing a pulley on an alternator.

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Kern Dog

Kern Dog

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I am helping a buddy do an A/C conversion in his car, it currently has a single groove pulley on a good alternator.
I have some dual groove pulleys here.
What is the process to change pulleys?
 
After you get the pulley off you have to separate the alternator case halves. You will need to press the new pulley on against the other end of the rotor. If you don't you WILL damage the bearings.

Go to mymopar.com and download your cars factory service manual or as close a year as possible. There is a section with all the procedures to do the job correctly
 
Dana67Dart said:
you have to separate the alternator case halves.
Click to expand...
Yep, then press the 2 groove pulley on. The front bearing is sealed but the rear is not so clean and grease with wheel bearing grease when going back together.
 
Kern Dog said:
I am helping a buddy do an A/C conversion in his car, it currently has a single groove pulley on a good alternator.
I have some dual groove pulleys here.
What is the process to change pulleys?
Click to expand...
some of the pullers and problems with new pulleys shown here
www.forabodiesonly.com

Alternator repair, a little show and tell.

I finally got around to fixing a squareback alternator I removed from the Barracuda a year and half ago. It came out because its output was weak. Thought I'd share some of the repairs here. Its not meant to be a complete 'how to.' First thing was to remove the pulley. This had nothing...
www.forabodiesonly.com www.forabodiesonly.com

Installation must be done with the case apart. Use an arbor or hydraulic press. Book says to use a force gage with it. Lacking that (I was) mark the depth on the shaft using a marker.
 
Or put the front case half together with the rotor in the freezer for awhile. Then boil the pulley in a can of water or heat it in an oven, it will either drop on, or you might have to "lightly tap" it on
 
Wasn't the shaft on Mopars threaded on the inner diameter so you could press/pull the pulley on using a special tool for that. I bought an OTC tool that is specifically made for doing this, installing & removing, when I was a mechanic & still have it, but I can't remember if Chrysler alternators had the threads on the in-side of the shaft. Pretty sure I've done them before. (Long time ago)
I will have to check now.
 
Crap....I didn't know about the difficulty of doing this. I don't have a press either...
Nevermind!
 
Kern Dog said:
Crap....I didn't know about the difficulty of doing this. I don't have a press either...
Nevermind!
Click to expand...
It's not difficult, but you do need a pulley puller and a press.
Seperating the case halves is easy. If its a round back, just be careful to keep the stater with the diodes or you'll have a soldering project on your hands.
If you were closer I'd tell you to stop by and we'd be done in hour.
 
They used to sell a tool for this that pulled the pulley and then pressed it on. The case has to be split.
My grandad had one when I was a kid and it was worth the time to rebuild alternator's and change alternator bearings
Now days you can usually buy a reman cheaper than pay labor so I have never looked for one if these kits.
35 bucks will probably buy an alternator with the correct pulley.
 
Mattax said:
It's not difficult, but you do need a pulley puller and a press.
Seperating the case halves is easy. If its a round back, just be careful to keep the stater with the diodes or you'll have a soldering project on your hands.
If you were closer I'd tell you to stop by and we'd be done in hour.
Click to expand...
A big vice will work too.
 
HankRearden said:
They used to sell a tool for this that pulled the pulley and then pressed it on. The case has to be split.
My grandad had one when I was a kid and it was worth the time to rebuild alternator's and change alternator bearings
Now days you can usually buy a reman cheaper than pay labor so I have never looked for one if these kits.
35 bucks will probably buy an alternator with the correct pulley.
Click to expand...

Not an alternator, but P/S had the threads to put pulleys back on.

IMG_20231023_132605_815.jpg
 
inertia said:
Not an alternator, but P/S had the threads to put pulleys back on.

View attachment 1716157437
Click to expand...
YEP! I just checked my OTC tool & it IS for removing & installing P/S pump pulleys. I also just took the pulley off of a square back alt that needs re-building & I'm in the process of removing the shaft from the front half of the alternator housing. Is the front bearing pressed into the outer housing? I don't want to mess it up & the bearing needs to be replaced. What's the trick? I've never taken one apart before.
 
Some of those PS pullers (old OTC) were reversible, and could pull both

I told ya, it's easy. You don't need a press. Go down to Oh Really's and borrow their puller, they should have one to loan. Toss the case/ rotor assy in the freezer for awhile, maybe an hour.
When you are ready, heat up the pulley, pull out the rotor on a hardwood block or aluminum scrap and drop it on, may need a few light hammer taps.
 
niceolddart said:
I also just took the pulley off of a square back alt that needs re-building & I'm in the process of removing the shaft from the front half of the alternator housing. Is the front bearing pressed into the outer housing?
Click to expand...
Shop manual is pretty good although IIRC the illustrations are slightly confusing.
Chrysler called the case castings shields. Rectifiers are in the rear half along with the brushes.
I think all of that is shown in the other thread.

There's a couple different versions of insulators and output studs. Keep track of what goes in the specific alternator.
This needle bearing is pressed in.
1698098608731.png

Covered in the other thread. I don't have additional specific guidance to offer on the depth - just what I posted there. Basically, the OEM needle bearing had ridges and that helped with the location. The flat ones like above should sit proud on the exterior, especially if the grease shield is used.

1698098471119.png


There are tools that help clear the casting but I don't think they are absolutely neccessary.

On the pulley end shield, there is a retainer to be unclipped.
1698099270890.png


1698099331066.png


1698099386215.png


Don't recall if I pulled that bearing off or not. Since I have no photos, probably not. If it was still good I wouldn't have replaced it.

Spun like a top when all put back together.
1698099724825.png
 
Mattax said:
Shop manual is pretty good although IIRC the illustrations are slightly confusing.
Chrysler called the case castings shields. Rectifiers are in the rear half along with the brushes.
I think all of that is shown in the other thread.

There's a couple different versions of insulators and output studs. Keep track of what goes in the specific alternator.
This needle bearing is pressed in.
View attachment 1716157475
Covered in the other thread. I don't have additional specific guidance to offer on the depth - just what I posted there. Basically, the OEM needle bearing had ridges and that helped with the location. The flat ones like above should sit proud on the exterior, especially if the grease shield is used.

View attachment 1716157474

There are tools that help clear the casting but I don't think they are absolutely neccessary.

On the pulley end shield, there is a retainer to be unclipped.
View attachment 1716157477

View attachment 1716157478

View attachment 1716157479

Don't recall if I pulled that bearing off or not. Since I have no photos, probably not. If it was still good I wouldn't have replaced it.

Spun like a top when all put back together.
View attachment 1716157486
Click to expand...
Thanks for the info. Very helpful. I guess I should have kept my 73 service manual.
 
I'm looking at it on my phone so I may be wrong. I can see how that pulls the pulley but I can't see how it will press it on.
inertia said:
That is the alternator tool, been using it 50 yrs .
Click to expand...
 
HankRearden said:
They used to sell a tool for this that pulled the pulley and then pressed it on. The case has to be split.
My grandad had one when I was a kid and it was worth the time to rebuild alternator's and change alternator bearings
Now days you can usually buy a reman cheaper than pay labor so I have never looked for one if these kits.
35 bucks will probably buy an alternator with the correct pulley.
Click to expand...
I had a friend that had a rebuilding shop for starters and alternators. He would just pop them on for me. I rebuilt them myself for many years myself but had him remove and replace the pullies when needed. It is difficult to do yourself. I ruin many.
 
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