B7100 - disassembling dynamo

[dextersl]

Hello all,
I have been on this forum for the past few months since acquiring my kubota and the wealth of information you all have provided through these forums have been very valuable.

I ran into the fan/dynamo not spinning issue and deduced, based on input from this forum, that my bearing seized up. I have already broken down the frontend and removed the dynamo from the engine. After opening the dynamo I discovered large amounts of shredded metal inside. I have since cleaned out the metal debris and now need to remove the old bearing. Can anyone provide any guidance on how the bearing is removed? It is proving to be a little difficult at the moment. I have attached some pictures of the dynamo below:

Thanks in advance for your help on this.

 

[Egon]

There should be a retaining clip in the second picture that holds the shaft in place.

Send me your email address and I can send you a PDF that shows the exploded view.

 

[dextersl]

Egon, thanks for the offer. I sent you the email. Is the ring you're referring to called:

Ref No: 090
Part No: 15261-95470
Description: CIR CLIP INTERNAL

I took a picture of the rear half of the dynamo and attached it below. If you look closely, you can see what I believe to be the clip you are referring to. It also looks as if there is another set bearings in the rear half of the dynamo behind the clip in the picture which I am assuming is part the stator assembly since there is no separate listing for that set of bearings.

So if the clip is on the rear half, then what is holding the bearing in the front half in dynamo-inside photo above?

 

[Egon]

The exploded view only shows the one bearing. But but from the exploded view remove the nut and clip and everything should come apart.

I never have taken mine apart. I ordered a new one and installed it.

The PDF is in the mail but it sounds like you already have one.

 

[dextersl]

Egon, thanks for the response and thanks for the email.

I finally got the front half of the dynamo disassembled. I ended up using a hammer and a punch to force the shaft out, after which the bearing finally came off. I attached some photos of the front half completely disassembled now.

I will order the new bearing next week and post a pick of what the new intact bearing should look like before installing it.

 

[Egon]

dexters, I was always under the impression my dynamo failed due to to much belt tension???

It failed at about the 1100 hour mark if I can remember correctly. The replacement was still working well at 3000 hours.

It may be something to consider.

Did you have any trouble getting the one miserable semi hidden bolt out when you were taking the dynamo off?

 

[lawn_king]

Load the new bearings up with fluid film when you put it back together.

 

[dextersl]

Egon, I had a heck of time getting that one miserable bolt off. I saw one of your posts though where you mentioned using one of those ratcheting box end wrenches, and ended picking one up with the 180 degree flex head and that finally did the trick.

lawn_king, are you referring to the brand name product "fluid film?" I am a novice, at this stuff, so never heard of them before. I checked out the website and they appear to have small aerosol cans you can purchase on-line and at our local John Deere dealer. I will make sure to pick this up as well, thanks for the recommendation.

 

[Egon]

ratcheting box end wrenches

Someone else use one of those. I bent a combination wrench to fit. Still in the bottom of my toolbox.

 

[grossgary]

lawn_king, are you referring to the brand name product "fluid film?"

in the automotive industry some manufacturers only pack bearings in shipping grease, it's only meant to prevent corrossion and provide protection during storage/shipping. it needs to be cleaned out and properly greased.

i'm assuming that's what he means, but i have no idea what kind of grease to use. i'd go with a high temp synthetic, but sounds like he knows better than i.

if you end up needing a part i probably have my old one sitting around, i replaced mine last year.

and if you have a 60" MMM i'd love a picture of the mounting points and hardware between the mower and tractor, mine is not quite right, though useable.

 

[dextersl]

grossgary, thanks for the info and offer. My B7100 is still down, I am getting ready to put it back together this week. My MMM (RC60-71B) is currently off of the tractor, once I get it back together and up and running I can take those pictures you asked for unless someone else has already provided them for you.

I have attached pictures of the new bearing and old bearing together in case anyone was interested in seeing it before I reassembled the dynamo. The first picture shows the front of the bearings with the damaged shield that popped off. and the second photo shows the back of bearing with a damaged shield still intact. The new bearing uses a rubber seal to protect the bearings on both sides as opposed to the metal shielding used on the old bearing.

 

[canucklehead]

hmmmm, my B7100 had an awful burning rubber smell and alternator belt wasn't spinning, or maybe it was alternator pulley wasn't spinning and belt was smoking. So this dynamo bearing could be my culprit? i haven't tore into it to try and diagnose. I guess loosening alternator and checking to see if that pulley turns easily will be first starting point and go from there. Where is this dynamo? Bottom of the belt loop?

 

[Gator6x4]

grossgary, thanks for the info and offer. My B7100 is still down, I am getting ready to put it back together this week. My MMM (RC60-71B) is currently off of the tractor, once I get it back together and up and running I can take those pictures you asked for unless someone else has already provided them for you.

I have attached pictures of the new bearing and old bearing together in case anyone was interested in seeing it before I reassembled the dynamo. The first picture shows the front of the bearings with the damaged shield that popped off. and the second photo shows the back of bearing with a damaged shield still intact. The new bearing uses a rubber seal to protect the bearings on both sides as opposed to the metal shielding used on the old bearing.

Don't pry or mess with the rubber seals. Those type bearings are called permanent lubricated bearings with no provision for injecting a lubricant. They are designed to operated in a dry environment such as the inside of a alternator or dynamo.

Good job.

 

[canucklehead]

Don't pry or mess with the rubber seals. Those type bearings are called permanent lubricated bearings with no provision for injecting a lubricant. They are designed to operated in a dry environment such as the inside of a alternator or dynamo.

Good job.

I've used a dental pick to pop off those seals and then inject more grease. They seem to have minimal grease. I'm sure they're probably engineered that way but I figure extra grease can't hurt. Reality is: probably only a tiny smidge of the grease is ever in contact with the metal pieces (ball bearings, cage, etc...) so probably what they put in is adequate but I figure it seized due to drying up so more grease will give longer life.