Kubota B6100 Dynamo

[Matt S]

I have a b6100 non-hydro 4wd and the dynamo is not working. Mind you I'm not a mechanic so I'm doing my best. Basically the tractor lights and horn haven't worked in some time but did work a couple years ago. When I jump start the tractor and have the jumper cables hooked up the horn and lights work, once disconnected they don't work. I was told my dynamo could be rebuilt so I removed it and took it in but the rebuilding shop promptly told me they didn't know what that was and they couldn't help me. I was mad to say the least - a new one is $300 Canadian.

So before I put it back on should I tear it apart? When it was on I measured 9v at the battery with the engine maxed out, at low idle I measured about 2v.

My questions are:

- Should I check anything before re-install
- After I reinstall how should I test it?

Thanks so much for any help you can offer,

Matt

 

[banjodunn]

G'day Matt and welcome to TBN have you tried putting a good battery in it as it sounds like your dynamo is actually charging if it was not you would not be getting a change in voltage with the change in revs i think you have just got a very dead battery with bad cells . Best of luck with it



Jon

 

[Matt S]

Unfortunately I didn't try that, I was told the battery was new when I got the tractor, and it looks fairly new. Maybe it needs water added? I know it was a bad idea to remove the dynamo but I wanted to get it fixed asap so I jumped in and took it out, I thought I tested it properly. Like an alternator I expected around 14v at the battery, when I found 9v I thought I figured it out.

I guess I can test it with any old battery, I got one in my mower or I can steal one from a car to try.

So you do not recommend taking it apart before I put it back in?

 

[banjodunn]

G'day matt no i would not pull it to bits yet i would definately try another battery before you go too far yes one from your car would probably be good enough to start it. Good luck with it



Jon

 

[allenr]

Initially, I was going to suggest checking that the power is going through the rectifier (the finned thing behind the dashboard).

However the change in battery voltage would tend to indicate that it is ok.

My experience is that a rectifier will fail more often than the dynamo.

 

[Matt S]

So I should put it back in and replace the battery? Once it's back in I would like some basic tests to try since I've learned this is not the same as an alternator.

Thanks all,

Matt

 

[DennisMI]

It looks like you're in Canada, so I found the Canadian web site for Kubota. This page can find dealers where they may have technical bulletins from Kubota: Kubota Canada : Manufacturer of compact diesel tractors, construction equipment, agricultural equipment, power washers and engines.

I wonder if your dynamo needs to get a charge back to it to tell it to charge. The 1990's Ford trucks are like that. They would get a wire that goes to the gauges that would corrode, and would prevent the alternator from getting a signal to charge. Ford had a technical bulletin that they won't show to the public to tell the dealer how to fix the problem without opening up the wiring harness. But this is just an example of what might be wrong.

 

[Matt S]

The part I'm not sure about is this. If it was the battery shouldn't the lights and horn work once the tractor is running? Why would the horns and lights work only when connected with jumper cables to my truck?

Sorry I'm an IT guy who has a hobby farm and tinkers on the side, I'm still learning!

Thanks,

Matt

 

[Matt S]

It looks like you're in Canada, so I found the Canadian web site for Kubota. This page can find dealers where they may have technical bulletins from Kubota: Kubota Canada : Manufacturer of compact diesel tractors, construction equipment, agricultural equipment, power washers and engines.

I wonder if your dynamo needs to get a charge back to it to tell it to charge. The 1990's Ford trucks are like that. They would get a wire that goes to the gauges that would corrode, and would prevent the alternator from getting a signal to charge. Ford had a technical bulletin that they won't show to the public to tell the dealer how to fix the problem without opening up the wiring harness. But this is just an example of what might be wrong.

Dennis - I remember reading that if I touched on wire to ground it would change the polarity of the charge or something? I'm not sure if that applies here, maybe someone knows more than me?

Thanks,

Matt

 

[DennisMI]

Dennis - I remember reading that if I touched on wire to ground it would change the polarity of the charge or something? I'm not sure if that applies here, maybe someone knows more than me?

Thanks,

Matt

I can't remember, it's a long time ago, but I think that was with the old generators early 1960's and before, before alternators. But someone with a better memory than mine can help there.