Alternator Dissassembly, Bearings - L3940

[fc1]

Hello friends,
The bearings of the alternator of my L3940 (2013, ~700hr, HST) became prone to squealing on cold starts, so I've removed the alternator from the tractor and partially disassembled it. My plan would be to install new bearings after I measure and order them.

The nose bearing should be pretty simple; I can press it out. The rear bearing has no access; do I press on the shaft and then use a puller to get the bearing off (assuming the bearing stays on the shaft)? Will the brushed surfaces pose a problem?

Some sources suggest there are three bearings... sure looks like two to me. Am I missing something?

Thanks in advance!

 

[ruger1980]

Download the WSM from the Kubotabooks website. It has all the disassembly/assembly instructions in it.

 

[fc1]

Download the WSM from the Kubotabooks website. It has all the disassembly/assembly instructions in it.

Doh! I have a copy of that; tbh it didn't even OCCUR to me to look for alternator disassembly instructions there. Thanks!

 

[GeoHorn]

If it doesn’t work out for you…. compatible parts-wise…or cost-wise… The chinese-copy-cat alternator from DB (amazon) for $69 (prime, free shipping, overnight)….. which I bought in 2018 is still working just great.

 

[Hugo Habicht]

Hello friends,
The bearings of the alternator of my L3940 (2013, ~700hr, HST) became prone to squealing on cold starts, so I've removed the alternator from the tractor and partially disassembled it. My plan would be to install new bearings after I measure and order them.

The nose bearing should be pretty simple; I can press it out. The rear bearing has no access; do I press on the shaft and then use a puller to get the bearing off (assuming the bearing stays on the shaft)? Will the brushed surfaces pose a problem?
View attachment 169880
View attachment 169881

Some sources suggest there are three bearings... sure looks like two to me. Am I missing something?

Thanks in advance!

It looks as if you have to pull off the slip rings first before you can pull off the bearing. Make sure you desolder the wires to the slip rings first, otherwise they will break and that could mean your stator is toast.

 

[PoTreeBoy]

It looks as if you have to pull off the slip rings first before you can pull off the bearing. Make sure you desolder the wires to the slip rings first, otherwise they will break and that could mean your stator is toast.

I downloaded that WSM out of curiosity. It still wasn't clear to me how to disassemble that bearing. It doesn't appear the bearing id can slip over the slip rings. Is the shaft hollow or slotted to get the leads past the bearing?

 

[Hugo Habicht]

I downloaded that WSM out of curiosity. It still wasn't clear to me how to disassemble that bearing. It doesn't appear the bearing id can slip over the slip rings. Is the shaft hollow or slotted to get the leads past the bearing?

I have no idea, never seen anything like it. Slots could be an option.

This is one of those things where you damage it on disassembly and then you are wiser how it should have been done correctly

 

[PoTreeBoy]

Looking at this drawing, it looks like the bearing may be able to pass over the slip rings. You should be able to tell once you remove the rear cover.

 

[Hugo Habicht]

Looking at this drawing, it looks like the bearing may be able to pass over the slip rings. You should be able to tell once you remove the rear cover.

View attachment 169898

That does not match what I think I see on the photograph 2 in post #1. But anything else would not make a lot of sense.

Pulling the rotor out of the rear housing should reveal more.

 

[PoTreeBoy]

That does not match what I think I see on the photograph 2 in post #1. But anything else would not make a lot of sense.

Pulling the rotor out of the rear housing should reveal more.

I saw it the same way. I'm hoping @fc1 will post a picture after he removes the housing.

 

[GreensvilleJay]

I've been here 4-5 times, and convinced toy need to remove the slip rings 'somehow' to then slide the bearing off. Also have to unsolder the wires to the sliprings. Have no idea IF the WSM explains that has to be done.

 

[North Idaho Wolfman]

I've been here 4-5 times, and convinced toy need to remove the slip rings 'somehow' to then slide the bearing off. Also have to unsolder the wires to the sliprings. Have no idea IF the WSM explains that has to be done.

There are mutiple different alternators for that model of tractor, and without the build info you're just guessing, Unless you have a crystal ball that you're consulting or stuck up and orifice that gives you great insight.

 

[GreensvilleJay]

Looking at the 2nd picture in the original post, you can see the shaft,inside the slip rings as well as the bearing(120) in the case +spacer (110). Interesting they don't show the rear of the shaft or the slip rings. they however show 100 to be rotor, bearing, spacer suggesting the need to buy the 'assembly'. All 3 HST versions use the same diagram, at least in Canada.The slip rings are smaller in OD than the spacer(#100),but greater than the ID of the bearing, at least when you look at both the drawing and picture. From a wear perspective, the front bearing (#060 ) will get most of the stress and fail much faster than the rear bearing. Since most techs won't have the required skill set or equipment to remove and replace the slip rings, I assume Kubota requires them to replace the 'rotor assembly'(#100).

 

[PoTreeBoy]

I've been here 4-5 times, and convinced toy need to remove the slip rings 'somehow' to then slide the bearing off. Also have to unsolder the wires to the sliprings. Have no idea IF the WSM explains that has to be done.

We all agree it's a puzzle.

I went to my L35 WSM seeking enlightenment there. It had identical instructions and a drawing of a bearing puller on the bearing, with no mention of removing the slip rings. The repair for under tolerance slip rings is 'replacement', but that may mean 'replace the rotor', as the parts diagram doesn't list the rings separate.

I may go to Messick's site and see if they have any actual pictures. And hopefully, OP will be back soon with a picture.

Edit: No joy at Messick's.

 

[TheOldHokie]

We all agree it's a puzzle.

I went to my L35 WSM seeking enlightenment there. It had identical instructions and a drawing of a bearing puller on the bearing, with no mention of removing the slip rings. The repair for under tolerance slip rings is 'replacement', but that may mean 'replace the rotor', as the parts diagram doesn't list the rings separate.

I may go to Messick's site and see if they have any actual pictures. And hopefully, OP will be back soon with a picture.

Edit: No joy at Messick's.

A new alternator is so much easier and faster.

Dan

 

[PoTreeBoy]

A new alternator is so much easier and faster.

Dan

Don't you have a hydraulic leak to fix somewhere?

I have nothing better to do, sitting around, waiting for covid to go away.

 

[TheOldHokie]

Don't you have a hydraulic leak to fix somewhere?

I have nothing better to do, sitting around, waiting for covid to go away.

Get well soon!

Covid is something I cannot afford

Dan

 

[whitetiger]

I have a hunch that if the bearing is avalible it most likely has a larger ID than the OD of the slip rings.