JD 670 Alternator

[Reg312]

Last winter, while pushing snow with my 670, The belt started to squeal and I smelt rubber and the battery light lite up. Since then I've run it 3 times. Battery light is still lite but starts easily (battery seems to have and hold full charge)but after about 10 - 15 minutes use it starts squealing and Smell rubber. With closer inspection, the itty bitty alternator is smokin hot to touch. Tension on belt is good.Took the belt off and alternator pulley won't turn. I'm not sure if it's supposed to turn freely when tractor is off or not, but that doesn't seem right to me. So -- Since the the belt is hooked to crank, waterpump (which turns freely) and Alternator I'd put money on the Alternator. So before I throw down $300 on and alternator. does my diagnoses seem right?

 

[zzvyb6]

A lot of alternators that ought to work for yanmar / JD tractors for under $100 free shipping on eBay...

 

[brin]

Last winter, while pushing snow with my 670, The belt started to squeal and I smelt rubber and the battery light lite up. Since then I've run it 3 times. Battery light is still lite but starts easily (battery seems to have and hold full charge)but after about 10 - 15 minutes use it starts squealing and Smell rubber. With closer inspection, the itty bitty alternator is smokin hot to touch. Tension on belt is good.Took the belt off and alternator pulley won't turn. I'm not sure if it's supposed to turn freely when tractor is off or not, but that doesn't seem right to me. So -- Since the the belt is hooked to crank, waterpump (which turns freely) and Alternator I'd put money on the Alternator. So before I throw down $300 on and alternator. does my diagnoses seem right?

You might want to check in your area for an auto electric shop that rebuilds starters and alternators...I have used one here in our are twice and it has saved me a lot of money..

 

[kennyd]

You might want to check in your area for an auto electric shop that rebuilds starters and alternators...I have used one here in our are twice and it has saved me a lot of money..

^^^^^^^
That is great advice. Find a local shop...the bearings are probably fried in yours.

 

[Reg312]

Pulled it off. Took it apart. Didn't realize how simple it was inside. Bearing was shot. Just happens I had a new bearing laying around. Cleaned it up. Put in the bearing. Turns freely now. Ran it for 5 minutes. Alternator did NOT get hot but was noisy. Think I'll run it as is for awhile before I take the plunge on a professional rebuild or and ebay purchase. Thanks for the replies

 

[RoyJackson]

A great conclusion!
Hope that replacement bearing holds up. But an alternator shop should be able to rebuild it for less then $100.

 

[Reg312]

A few hours of Brush Hogging will tell the tell. Think I'll keep one eye open for a new one or call and Alt. shop for estimate. Thanks for the replies

 

[Gale Hawkins]

I just ordered a new one for $105 shipped for our 1983 JD 310B TLB. I have had mixed results with rebuilds so I am trying a new one. When I get it and installed I will try to note the results. At least it should look more impressive than the old one with yellow over spray.

Rebuilds really make sense for hard to find special apps that cost 3x the rebuild cost. When the prices are equal (most often the case with common units) it really is a toss up. There is more of my labor involved in going rebuilt.

 

[dklistul]

I always rebuild my own (never done on from a JD but have rebuilt lots of alternators from cars and pickups). Amazing what a set of bearings, brushes and diodes can do to bring an alternator back to life, for a fraction of the price of a new, rebuilt or repair shop unit. Sometimes, the hardest part is getting the slip rings nice and clean.

If your bearings are noisy, you might want to get them outta there soon. And check the rear bearing as well as the front.

 

[Gale Hawkins]

Well we got our "internet" JD model specific installed last night. It did not have the JD connectors but worse was one lead short coming coming out of the voltage regulator that feeds back to the dash.

I emailed the seller and learned I should not have expected it to be have fit what he stated it would replace. After I found the factory looking test results included in the box was a shame I really did get upset. There was no markings at all but the test results was S/N specific and stated it had an internal voltage regulator. Well when this alternator was designed in the 60's they were still external regulated since that technology came out in the early 70's. Well the seller is another story that is unfolding.

The good news is the old external voltage regulator worked when I swapped it over to the new one that was short a lead and I did not know a work around.

Now the alternator light is bright like the oil pressure light when the key is turned on and it goes out when the engine starts. Well there is a red/orange glow point that can only be seen when it is dark but that may be normal. The glowing light clearly goes out after it starts.

In the process of tapping of the old pulley a lot of dirt came out of the alternator. It seemed to be the 27 year old OEM alternator. I will pass on ebay only parts dealers in the future for electrical parts for a 27 year old machine.

It took about 3-4 hours to complete the job because I just could not stand to put it back on with the dirt still there so we degreased from the steering wheel forward and washed it all up well with the alternator off and in a dry place.