B7500 dyno / alternator

[jcato]

Folks,

Just 'lost' my dyno (?? alternator) on my B7500 today. In trying to ascertain what direction to take (rebuild / replace), I'm now with doubts as to what, exactly, is on the tractor -- is it a dyno or alternator? Appears the former (i.e. solid (appearing one-piece) case behind the pulley). Found something online about a 'conversion' to an alternator on a B7800.

I guess the question now is 1) exactly how do I tell if this is a dyno and, 2) if converting to an alternator (found one on ebay for about $70) -- are we talking new wiring harness and other items? Are there sources for this outside of my Kubota parts counter?

Is the conversion (if that's indicated) to the alternator a better option (than rebuilding / replacing the dyno).

Advice respectfully requested.

Thanks in advance,

-- john.

 

[ETRon]

I don't know much if anything about the B series specifically but a couple points I can help on. The Japanese (and perhaps others) refer to an alternator as a dynamo regularly. In your place I'd remove the unit and either take it to a local repair shop or at least call one with the numbers and check our what ya have. All the Kubota alternators I've come across have been Denso alternators and are readily rebuildable.

Ron

 

[jcato]

Thanks Vic & 'ETRon' -- I broke things down and simply had a bearing seize - so I replaced all three (2 front, 1 rear). Got everything back together this afternoon and fired 'er up and things are (seem to be) fine now.

One point I noticed on this alternator rebuild -- the (pulley) shaft seemed to have a 'shoulder' (very slight - maybe 0.0005 or 0.001") that would not have been a sliding fit - towards the front (pulley) end. Ended up pressing the two front bearings on the shaft (via the inner race) and then sliding the stator (?) onto that assembly. Then, pressed the rear bearing into the stator casting. This was the only way I saw to get things together - but was concerned that the sliding fit of the front bearings (outer race) might spin in the stator. I'm going on faith that tightening everything down will hold all the races secure. If anyone sees any problems with this assembly procedure, please note it for me (and other hapless 'first time (kubota) alternator rebuilders' <g>).

Thanks again,

-- john.

 

[ETRon]

I can't say your assembly follows "exactly" like one would for others I've rebuilt but I looks like it was in capable hands. The bearing presses you mention are what is "normal" for most o the ones I've built though. Pleased for ya!

 

[Groo]

one thing nice about a home rebuild is; even if you screw it up, you're only out a broken alternator.

sounds like you did fine.

 

[theboman]

Brand new on OTT and first time post.

I lost my dyno (I think).... Heard a squeal, then noticed the battery light on and smelt a stink...

Where to buy, approximate cost, what size bearings do I need?


Thanks!
Bo

 

[bruceatlam]

Brand new on OTT and first time post.

I lost my dyno (I think).... Heard a squeal, then noticed the battery light on and smelt a stink...

Where to buy, approximate cost, what size bearings do I need?


Thanks!
Bo

Your best bet would be to take it apart and take the bearings with you to your local bearing house ---- they can match them for you. The bearings are probably $5.00 or so each.

 

[theboman]

Thanks Orange Tractor Talks!! $20 and 3 bearings later the local altenator shop got me all fixed up!! Works like a charm.

 

[Dennis]

The bearings seem to be the most common problem.

Be careful when replacing them as the magnets in the dynamo get brittle with age and can crack off.

I got a 2nd hand dynamo for free just to get the magnets and housing.

Problem is nobody can move the seized front bearing from the shaft of this dynamo so I can use the housing and magnets in my old dynamo.

Tried all sorts of pullers, tried heat, tried a variety of rust release fluids (soaked the bearing and shaft for 24 hrs). Even my auto electrician could no get it off

Anybody got any other techniques for removing a seized bearing that won't damage the nearby magnets with excessive shock or heat.