580SE Alternator Fan Loose

[bowen]

Back in 2011 I had the alternator rebuilt and they told me the fan bolt was loose so they tightened it.
They said the loose fan caused the alternator to overheat and fail.

Now, fast forward about 125 hours running time later.
Last week I heard a new intermittent chinky chinky noise when it was running.
It was most noticeable as I shut it off and the engine was spinning down.
What I found was that the fan on the alternator was loose again.
It would just free wheel from my finger with the engine stopped.

I unbolted the alternator and was able to tighten this end/pulley nut, 15/16" I think, so the fan is now tight.

So the question is.
Why is this working loose? Is it common? Does it need some lock-tite on it?
And is that all that holds the fan? Do I need to take it apart to replace a keyway or some part missing?

After that 1st repair I did replace the tensioner, belt and hydraulic coupling.
My new tensioner is always shaking somewhat and I wonder if this is normal.
It's always quiet but that tensioner spring really gets a workout.

 

[Tinkerer]

When you refer to the fan, are you talking about the alternator pulley ? No key in the key-way ? The tension-er should not be pumping constantly. It may need to be replaced.

 

[Delmer]

The crankshaft pulley is the first place I'd look for out of roundness. Or any of the other pulleys being bent, especially any of the pulleys that bolt on like some fan or water pump pulleys. That wobble is being transmitted to the tensioner and alternator, that's my guess.

 

[jimg984]

look for a piece missing on the drive side of the belt,,, belts are hard change, they often get used past the replacement point

 

[Shimmy1]

How did you tighten the pulley nut? If you didn't, I recommend you pull the alternator and hit it with a good ½" impact. Just hold the pulley and let it hit for 3-4 sec. If that doesn't do it, you might need a new pulley. Is it a tapered shaft with a wedge or straight?

 

[bowen]

How did you tighten the pulley nut? If you didn't, I recommend you pull the alternator and hit it with a good ½" impact. Just hold the pulley and let it hit for 3-4 sec. If that doesn't do it, you might need a new pulley. Is it a tapered shaft with a wedge or straight?

That's exactly what I used to tighten the nut.
The 580SE used 2 alternators, but I think it's the D121831.
http://www.colemanequip.com/Case-W1...Electrical-System-4x/D121831-ALTERNATOR-09hl/
I can't tell from the drawing exactly what hold the fan, unless it's just squeezed in behind the pulley.

The tensioner I installed was an aftermarket... It's not that old and the belt still looks new.

 

[hookedondiesel]

The tensioner shouldn't be getting a work out like you described, it should barely even move.
Something is out of alignment, the nut on the alt turns the same way as the belt does, so it shouldn't loosen up if tightened correctly.

 

[bowen]

The tensioner shouldn't be getting a work out like you described, it should barely even move.
Something is out of alignment, the nut on the alt turns the same way as the belt does, so it shouldn't loosen up if tightened correctly.

Well I have not checked alignment.. ointhead
I have the loader cylinders off being rebuilt so I can't crank it for a few days.

I'm worried that this vibration may be related to the hydraulic pump shaft.
I'm running on a worn splined shaft as per this thread link below.
Back then I asked how long it would last. Well so far the answer is at least 125 hours.
https://www.heavyequipmentforums.com/showthread.php?26901-580SE-Hydraulic-Pump-Coupling&highlight=

 

[Tinkerer]

I see in the parts book the 580SE's used three different alternators. You may need a new pulley and wedge if yours spun freely enough to wear the combo to the extent that the wedge cannot bind up the shaft and pulley. Hopefully the alternator shaft is OK.