What to do when alternator rotor is frozen to shaft?

man oh man. I went out there to crank away on the engine, getting ready to finally split the case open so I can swap out the transmission. only thing standing in my way is the alternator.

So, I get the bolt out that holds the rotor in no problem. Cool, looking good.

I find something with the right threads for the alternator, and take another smaller bolt and cut it down to the right length to slide down inside. I tighten the puller onto it, and tighten, and nothing.

Hammer on it, nothing. Tighten (more than I feel comfortable) nothing. Try different length bolts in different configurations... nothing nothing nothing.

so... what now?

The only last resort I have is getting a more appropriate puller bolt that's harder. What I'm actually using is a pipe fitting that appears to be brass, and just happens to fit the threads perfectly. I'm getting quite a bit of torque on it, but it might be soft enough that its absorbing just enough of the pressure to keep the alternator from breaking loose.

Anyone else had issues with stuck rotors?

 

First, don't try to get by without the right tool for the job. You need to get the correct 16X1.5mm RH thread puller bolt and hardened steel pin in the hole. Tighten the bolt as you've done against the pin and whack it solid with a BFH (Big F'N Hammer) no baby tapping. After a couple whacks, tighten the bolt a little more and continue 'till rotor pops off.

 

+1

The right tool always makes it easier. Sometimes a improvived tool works, sometimes not. Don't keep trying you may strip the threads in the rotor.

 

A Universal "Harmonic Balancer / Pully Puller" and several Metric Bolts long enough to Thread into the Rotor will do the trick.

Tighten the Bolts through the Crows Foot evenly.
Take-up the Slack on the Rotor.
Tighten the Puller 1/4 of a Turn at a time.
After each time you add more Torque to the Puller, ... Strike the Puller's Center Tool Bolt on the end with a Hammer.

Add more torque.
Strike the Puller Bolt.

The Rotor will come free.

(Treat the Shaft the Rotor goes on with Grease or AntiSeize.

 

I bought the reasonably priced MotionPro extractor and, using my electric impact gun, have successfully brought every rotor out, no exceptions. Dab of antiseize on the shaft when re-installing and life is good. It won't mess with the clamping friction too much and keeps anything from weeping/wicking between the shaft and rotor to corrode them together.

 

By the manual you will be putting your rotor back on, assuming you get it off, to a specified 39.8 lbf ft torque. That's a lot. You won't be getting that with a regular rachet. So don't expect it to be easy to get off.
For someone reading this who, like me, doesn't get it, after you remove the bolt "holding" the rotor on you reveal two sets of threads. One, the inner set, that the bolt you just removed screws into, and another, larger thread which is closer to you, looking in, that the unthreaded portion of that bolt passed through. You slip your "rotor puller attachment" ie. the pin into the interior thread hole. The pin is long enough to just stick out of this hole. You use your "rotor puller tool" (which is the bolt described below) to screw into the outer, larger threads. When that bolt threads through and hits the pin inside, it can't screw forward anymore so the rotor is pushed back, off its conical shaft.
I recently popped my rotor (after wasting time with unsuccessful procedures and nearly damaging it). I read all the advice on this site and for everyone else reading along and trying to figure it out it's important to understand what these guys here (who do know what they're talking about) are really saying.
1. You need a 16mm bolt with a 1.5mm Right Hand thread pitch. Go to Auto Supply or fastener shops and keep asking until you get exactly this. It will cost about $2-$3. It should be about 1.5 - 2 in long (which is about 4-5 cm long). If it's longer doesn't matter , but I don't know what the minimum is. NOTHING ELSE WILL DO, or you will just strip the threads in the rotor, and then you're really in trouble.
2. The pin is a hardened steel shaft about 1/4 inch diameter and about 4cm long. I've seen others recommend cutting off a bolt to make the pin. DO NOT FOLLOW THIS ADVICE. It will not be able to take the tremendous pressure of the bolt bearing down on it ie. the pressure of that rotor on the shaft. It will bend and damage those interior threads and then you will not be able to get that original rotor bolt back on later. Rule of thumb - if you can cut it with a hacksaw it is not nearly hard enough. Also, it should be FLAT on both ends so it doesn't get forced sideways against the interior threads. I actually used a hardened steel hex key that I cut with a grinder.
I never had to resort to hammering. Don't forget, ultimately you are hammering against your cast crankcase. If you have the right bolt and a hardened steel pin you can just turn the bolt (rotor puller) and POP, off it comes. Really, with a POP.

 

Well said Snooker. Buggered threads are a huge headache. Thanks for the write-up. And you are right about the POP.

 

By the manual you will be putting your rotor back on, assuming you get it off, to a specified 39.8 lbf ft torque. That's a lot. You won't be getting that with a regular rachet. So don't expect it to be easy to get off.
For someone reading this who, like me, doesn't get it, after you remove the bolt "holding" the rotor on you reveal two sets of threads. One, the inner set, that the bolt you just removed screws into, and another, larger thread which is closer to you, looking in, that the unthreaded portion of that bolt passed through. You slip your "rotor puller attachment" ie. the pin into the interior thread hole. The pin is long enough to just stick out of this hole. You use your "rotor puller tool" (which is the bolt described below) to screw into the outer, larger threads. When that bolt threads through and hits the pin inside, it can't screw forward anymore so the rotor is pushed back, off its conical shaft.
I recently popped my rotor (after wasting time with unsuccessful procedures and nearly damaging it). I read all the advice on this site and for everyone else reading along and trying to figure it out it's important to understand what these guys here (who do know what they're talking about) are really saying.
1. You need a 16mm bolt with a 1.5mm Right Hand thread pitch. Go to Auto Supply or fastener shops and keep asking until you get exactly this. It will cost about $2-$3. It should be about 1.5 - 2 in long (which is about 4-5 cm long). If it's longer doesn't matter , but I don't know what the minimum is. NOTHING ELSE WILL DO, or you will just strip the threads in the rotor, and then you're really in trouble.
2. The pin is a hardened steel shaft about 1/4 inch diameter and about 4cm long. I've seen others recommend cutting off a bolt to make the pin. DO NOT FOLLOW THIS ADVICE. It will not be able to take the tremendous pressure of the bolt bearing down on it ie. the pressure of that rotor on the shaft. It will bend and damage those interior threads and then you will not be able to get that original rotor bolt back on later. Rule of thumb - if you can cut it with a hacksaw it is not nearly hard enough. Also, it should be FLAT on both ends so it doesn't get forced sideways against the interior threads. I actually used a hardened steel hex key that I cut with a grinder.
I never had to resort to hammering. Don't forget, ultimately you are hammering against your cast crankcase. If you have the right bolt and a hardened steel pin you can just turn the bolt (rotor puller) and POP, off it comes. Really, with a POP.

 

???^^^

 

I was using a 20" breaker bar to apply torque to the puller bolt I was using. Definitely not question of amount of torque. By my estimation from having torqued a lot of lug nuts over the years, I'd say I was probably putting 60+ lbs of torque on that sucker.

Other than that I was pretty much following that writeup to a tee. The only difference being neither my "pin" nor my "puller bolt" were made of hardened material, so perhaps they were absorbing too much of the force and not applying it directly enough to the rotor.

I just called the local yamaha dealer and had them order the actual tool for me, as it was only 13 bucks, which seemed pretty reasonable! I'll let you guys know how it goes

 

ooookay. This is not getting better.

I got the tool from Yamaha, but it was just the bolt, not the pin. I made a pin by cutting down an allen wrench, and that seems to be working okay.

This time, I put a torque wrench on it so I could measure how much I was torquing it. I got up to 40lbs... hammered on it, 45.. more hammering, 55lbs, then gave up.

Then, after that, I notice something was amiss... I spun the rotor around and the bolt wobbled... it's slightly angled when screwed into the alternator, as if it was cross threaded... except it's not cross threaded. Every time I threaded anything in there, I always started it several turns by hand.

The only thing I can figure is that in torquing/hammering on it (before, with the brass piece) I actually managed to distort the shape of the threads inside the alternator. There was some slight metal flaking inside, suggesting that I'm a couple pounds of torque away from stripping the threads out entirely.

My pin (used to be a 6mm allen wrench) seems to be holding up well, with no bending, but I was putting enough torque on the tool that the tool itself has an impression of the allan wrench in the end that's about a millimeter deep.

Nothing budged.

I have absolutely no idea what to do, at this point. Please help

 

Tresch, in my last post I mentioned that I had nearly damaged my rotor, too. Like you, I had a very close but not exact bolt which threaded easily by hand for the first few turns and I, like you, thought I was turning the bolt against the pin as I torqued it further. But we weren't. The threads on the rotor are hard enough that you can apply as much torque as we were and all you're doing is deforming the threads, not pushing against the pin. Lucky for me, I gave up early enough that when I got the proper bolt, I was still able to use the threads on the rotor to get the rotor off.
For anyone reading this and intending to take the rotor off, you must have the EXACT size and thread pitch. (16mm X 1.5 RH pitch).
As I had somewhat damaged my rotor threads (as you have done), I was already thinking about what to do next if the proper "tool" was no longer able to do the job. Giving up and bolting the rotor back on was not an option. The only thing I could think of was to rig up a puller. My goal then would be to get the rotor off, in all probablility damaging it beyond further use, but without damaging the surrounding area or the conical rotor shaft. A new rotor is expensive but at least it can be replaced. I think that is where you are at now.
For others doing this, know that fudging on the "tool" will lead to very troublesome and expensive complications. You don't have to buy the actual Yamaha tool ($30 in my town + pin). I paid $3 for tools described above. Remember the importance of a hardened steel pin. If your "pin" bends you will damage the interior threads and that's a worse problem than Tresch now has.
I'm a no-talent beginner, but I would not follow the hit-it-with-a-hammer advice. The force of that hammer blow will be taken first by the threads in the rotor. The threads will have to deform to some degree before the force can be directed against the head of the pin, and the equal and opposing force of the pin can push back against the bolt, then the threads, and thereby push the rotor back. Ultimately you will always be relying on the strength of those rotor threads to push the rotor back. I advise anyone to get proper "tools" and follow the procedure out-lined in the manual.

 

Welcome to the site Snooker !
I'll be needing this advise soon enough.

 

When a Proper Fitting Pulled is attached to the Rotor and Torque applied to the Threaded Center Rod that makes contact with the Shaft, ... Once the Tool is TIGHT and Cannot be turned further, ...

COMMON PRACTICE is to Strike the Pullers Center Bolt with a Hammer.

With EVERYTHING "TIGHT" the blow is simply an IMPACT Strike that causes the SHAFT to receive the IMPACT and Everything else to remain FIXED under Pulling Torque.

The Impact causes absolutely NO Damage to THREADS.
The IMPACT forces the Shaft to move IMPERCEPTIBLY in the Vector of the Impact.
At the same time, ...
The TORQUE applied to the PULLER Holds the Rotor from Moving in the Impact Vector.

The Rotor MOVES >> IMPERCEPTIBLY toward the Pulling Force.

The resultant factor will disengage the Rotor from the Shaft, ... one the Rotor moves enough to no longer be seized on the tapered shaft.

This isn't a Maneuver of Anger and Frustration because the thing is stuck on there and you're pee'd-off and need something to beat on.

It's how you use the Tool.

It's applied Science.

 

KROIL: http://www.kanolabs.com/google/

Then use the tool as Rick suggests, get it good and tight and give it a good smite.

 

get rid of the pin, bolt right on the shaft, grease the bolt, threads and the end, tighten and pound till it's real tight, tighten again then heat the rotor, tighten again them pound, sometimes taps on the edge of the rotor while the bolt's tight helps

 

When a ROTOR is particularly stubborn, ... it is not uncommon to see the removal become a "Two Man Job"

One guy applies Turning Torque on Center Bolt of the Puller, ... using a 1/2" Drive Socket and a 18-Inch Pry Bar.

The 1st guy Tightens the Bolt ... removes the Tools ... allows the 2nd guy to apply a couple of Impact Blows to the Bolt ... and then, puts the Tools back to it and tightens it right-up some more.

When the Rotor finally "POPS" loose, ... is scares the heck out of both of them!!!

 

thanks for the encouragement guys!

I suppose the only thing worrying me right now is that my threads are not quite right. I'm going to see if I can get a hold of a thread tapper of the same size just to chase the threads and get them cleared out from the nastiness of my previous attempts, then I suppose I'll just go for broke!

 

Yeh, clean / re-tep the threads, i do as Polock says, only i grind a 'nose' on the end ef the bolt.
How are you holding the rotor from turning ? I use the extension bar from the 1/4" drive socket set

 

You need a Flat-ended "Bottom Tap" ... not a Pointed "Through-Tap".

Cut new Threads the Next Size-over.
Get Hardened Bolts to use with the Puller.
Washers, ... too.

To loosen the Nut on the Shaft.
Use Socket Extensions as depicted in the photographs.
Protect the Case and Air Cooling Fins from damage by covering the Extension by cutting a slice and sticking a Tennis Ball or a Hand Ball on the End.

Use a Long PRY Bar.
Use a 6-Point Socket
Get everything "Lined-up" and apply STRONG Un-do Torque on the Pry Bar.
Strong, steady, heavy pressure.

Then, have someone give the PRY BAR a Swift, Strong, Hard-Impact with:
A Hard Wood Hammer Handle
Plastic Mallet
A section of 2 X 4
A Baseball Bat (Wood)

Be sure that you are applying HEAVY Torque to the Nut during the Impact.
The ONLY thing you want to move, ... is the NUT.