50DN belt drive pulley

[Tony LEE]

The alternator quit charging last week because the pulley had come loose and the belts shredded. Doesn't worry me at the moment because I'm using the house solar system to keep both the house and engine batteries charged. Trouble is I can't run the original bus aircon and with a two week stopover in a major city coming up, soon will be a good time to fix it ready for the summer.

The pulley is completely loose on the shaft - flopping around and can be moved about 3/8" axially and I can see part of the spline. The "bolt" is still screwed tightly into the end of the shaft so can someone tell me how the securing system works - some sort of taper-lock system perhaps. Is that bolt a left hand or right hand thread and if I undo that bolt, will I still need a puller to get the assembly off the shaft.

Also since my shoulders are still recovering from removing and replacing the whole alternator because of a shorted stator winding a few weeks ago, it would be nice to be able to fix it while it is still in place. Any opinion on whether that should be possible.
If an in-place fix is not feasible I'm almost tempted to remove the 2 pulley end alternator mounting bolts and then split the alternator at the pulley end and withdraw the rotor leaving all the heavy part sitting on the engine.

thanks

Tony

[Ncbob]

Tonylee, can I identify with your problem...you bet I can.  Just been through the same thing...but in my case it was my stator that was shorted.

Now, to the pulley.  Mine, on my MC5, came of with the fan but the nut on the rotor must be removed and yes it's a right hand thread. You should be able to get a 1/2" impact wrench in there to loosen it. My fan has 4 tapped holes spaced about 90 degrees apart. They might be 1/4-28 or 5/16-24 but I'm certain they'd be fine thread.  I would think that a bridge puller of the right width would be the answer to pulling both the pulley and the fan. Since you recently replaced the rotor it shouldn't be too tough.

Good luck with the project and let us know how it comes out.

NCbob

[Tony LEE]

Was my stator shorted as well so I've never had the pulley off because the drive end just comes off with the end shield and rotor and pulley all in one piece. My bearings had absolutely no slop in them so I didn't disassemble that section.

Mine is oil cooled but the smaller bolts are still there even though there is no fan. I assumed they actually held the 4 groove pulley on to the hub and the hub is held on with the large centre bolt

[Sammy]

Tony, sounds like the splines on the rotor are wiped out. Rotor has straight splines.
Remove the pulley from the rotor and check splines on both parts.
Sometimes rotor will break apart too - welds break.
You can seperate the 50 DN alternator as you mentioned. There's an o-ring seal that goes in a machined groove of the stator, then is covered by the cast drive end.
Let us know what you find......
Sammy 

[Tony LEE]

Just an update for future reference.

Was quite easy to get just the rotor end off and leave the heavy part still in position.

Fault causing the floppy pulley is the splined sleeve that wedges the pulley onto the splined shaft was broken into 4 pieces.

Trick now will be to see if the Delco dealer in Perth can find a replacement. The shaft has 17 splines while the one he was looking at on the parts list has far fewer.

[Ncbob]

Tonylee, I know my rotor is good....let me count the number of splines. If you need it you can have it for the shipping costs. It'll be heavy though.....

Bob

[Tony LEE]

Thanks Bob.
My stator shaft seems in pretty good condition and a slight amount of spline distortion where the splined sleeve clamped on to the shaft can be touched up enough to slide the new sleeve on. 
What I need is the pulley assembly and the supplier is checking interstate stocks or will take a pulley off a new unit.
Thanks to a pretty good solar system, I can easily keep the engine battery topped up so as long as I don't do heaps of night driving, so the loss of the alternator is no big deal now that we are back down south out of the hot and sticky tropics and don't need the bus aircon.

[A previous post related the story of a nephew using a puller wrongly and breaking the outside flanges of the outer pulley sheave and someone has done the same to mine in the past and built the wall up with weld so it is a bit rough and the pulley probably should have been replaced anyway. Have to now.]