B4200 Dynamo Froze Up

[apn73]

I had a belt fail and the engine in my B4200 (1989, diesel, geared, 4wd) get hot and blow the whistle. Upon inspection it would seem that the dynamo has frozen, is this common? You see where the belt kept spinning on that pulley and eventually broke. The dynamo was initially frozen, but after I turned it a couple of time, it freed up. Well, it felt notchy. I'm guessing that the dynamo should spin smoothly and freely? Probably should replace it just to be sure? Anything else to replace while I'm in there?
Thanks,
Adam.

 

[lsmurphy]

http://www.orangetractortalks.com/forums/search.php?searchid=548863


And not a single poster posted a PN or a cross reference number........go figure

 

[apn73]

Thanks for the reply, sometimes I forget to do searches when I'm in the heat of the moment. I'll give Lashley a call tomorrow to see what they get for a new one. The bearing replacement sounds cheap, if you can get the bearings out. It was charging just fine, just doesn't spin anymore. I'm in position where I don't feel as though I've got the time to fiddle with it.

 

[apn73]

I have a B4200D tractor and the dynamo part number is 15973-6401-0, it's still and active and valid part number. Let the record reflect that this dynamo/alternator/water pump uses NSK 6201Z bearings, they are sealed bearings as you would expect in this application. And I still have to buy a new one because I don't like the look of the windings.

 

[chwkrvo]

How do you remove the dynamo assembly from the water pump to remove & replace the bearings inside the dynamo of a B4200d tractor model? The engine fan is off already.

 

[North Idaho Wolfman]

How do you remove the dynamo assembly from the water pump to remove & replace the bearings inside the dynamo of a B4200d tractor model? The engine fan is off already.

Just to be clear you don't have a water pump.

The back of the dynamo housing is just a water port.

You will need to unbolt the housing, the bottom bolt will be real fun it, super tight in there, then when you have it apart you can disassemble the dynamo.

If you need to see more search B7100 dynamo, that will give you the same setup and several on here have done the repair/rebuild.

 

[85Hokie]

How do you remove the dynamo assembly from the water pump to remove & replace the bearings inside the dynamo of a B4200d tractor model? The engine fan is off already.

READ this:

http://www.orangetractortalks.com/forums/showthread.php?t=24290

as NIW said - getting the bottom middle nut off can be fun - putting it on is even more fun! But once the whole thing is complete.....you get to say "atta boy"

 

[chwkrvo]

Just to be clear you don't have a water pump.

The back of the dynamo housing is just a water port.

You will need to unbolt the housing, the bottom bolt will be real fun it, super tight in there, then when you have it apart you can disassemble the dynamo.

If you need to see more search B7100 dynamo, that will give you the same setup and several on here have done the repair/rebuild.

It sure is tough getting the centre bottom nut off! WOW. Bent and shaped a wrench to go around corners to get at it. Thank you very much for all your input. Owned the tractor for 25 years.

Anyway, I replaced the 2 bearings and checked the wiring. Everything looked good, no burnt wires anywhere, etc, cleaned up the black soot inside and put it back together. It runs great. Output of the 'maintenance' dynamo at the battery when running is around 12.8v depending a bit on tractor rpm would this be about normal after 25 years for a dynamo?

 

[85Hokie]

"it runs great. Output of the 'maintenance' dynamo at the battery when running is around 12.8v depending a bit on tractor rpm would this be about normal after 25 years for a dynamo?"

I would think at close to WOT or even at 75% you ought to be closer to 14.4

 

[100 td]

I would think at close to WOT or even at 75% you ought to be closer to 14.4

X2
However, as it has probably been slipping and not outputting for some time, your battery may be low and pulling the voltage down while it accepts a charge, so it may take some time to see higher voltages until the battery charges up at tad. (It may also have reduced residual magnetism in the dynamo and therefore not be as efficient as when new)

So either stick a trickle charger on the battery for 24 hours to give it a top up, and recheck at 3/4 to full throttle, or check after at least 5 hours working hard with lights off. (at ~3/4)