B7100HST New or Old version and service questions

Vigo

Well-known member

Equipment
B6100, B8200
Jan 9, 2022
595
340
63
San Antonio Texas
Engine sounds are VERY tricky through video becomes sometimes microphones and speakers can make some sounds seem MUCH louder or quieter than they are in real life.

The only thing i heard from the video sounded like valvetrain noise. I am not sure because i've never had to take a valve cover off of any of mine (because these things rock) but i am fairly certain there is a manual valve lash adjustment in there. If that's the case i suspect adjusting it to spec would reduce the noise i was hearing. But again, from a video.. take my suggestions with a grain of salt.

I do plan to look into valve adjustment on my b6100 as it's starting to make more of that sort of noise. Its a bit over 3000hours. My 7100 @ 700 and 8200 @ 1000hrs have less of that sound.


As far as 'wide ags', the most likely thing to look for would be 29x12.50-15 'trencher tires' and 23x8.5x12 ag/r1 for the front. That would usually be the rear size for a smaller garden tractor but would go on the front in this case.

I just bought some 31x12.50-15 turfs but have not mounted them up yet.
 
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Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
Engine sounds are VERY tricky through video becomes sometimes microphones and speakers can make some sounds seem MUCH louder or quieter than they are in real life.

The only thing i heard from the video sounded like valvetrain noise. I am not sure because i've never had to take a valve cover off of any of mine (because these things rock) but i am fairly certain there is a manual valve lash adjustment in there. If that's the case i suspect adjusting it to spec would reduce the noise i was hearing. But again, from a video.. take my suggestions with a grain of salt.

I do plan to look into valve adjustment on my b6100 as it's starting to make more of that sort of noise. Its a bit over 3000hours. My 7100 @ 700 and 8200 @ 1000hrs have less of that sound.


As far as 'wide ags', the most likely thing to look for would be 29x12.50-15 'trencher tires' and 23x8.5x12 ag/r1 for the front. That would usually be the rear size for a smaller garden tractor but would go on the front in this case.

I just bought some 31x12.50-15 turfs but have not mounted them up yet.
Yeah agree hard to hear through speakers etc, it is a lot louder in real life, but I thought there might have been a bit of a noise there, thanks, I will look into valve adjustment and see if it is something I need to do.
 

Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
The other night when I was doing some tests with the 3 pint to see how much it could lift, which was about 250kgs / 550 lbs which was pretty much what you all said yours lifts. I had the weight disrupted as evenly as possible on a standard size pallet. So that is reassuring :)

One thing I did notice when running the tractor at night is the exhaust was getting sucked straight into the radiator, which can't help with cooling. I really dont want to put it vertical because I dont want to breath it in either.

What have other people done to try to keep the exhaust smoke out of the radiator?
 

Lil Foot

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Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,578
2,636
113
Peoria, AZ
I really dont want to put it vertical because I dont want to breath it in either.
If you take it high enough, neither you nor the radiator will breathe it in.
I haven't smelled my exhaust since I went vertical.
current.jpg
IMG_0222.jpg
 
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Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
I mentioned in a previous post when I got the B7100, the driveshaft cover was spinning with the shaft. The boot is not in the best condition and needs replacing (yet to replace). I finally got a chance to put the front drive shaft back in and tapped up the rubber boot to make it last a bit longer.

I think the cover was spinning for so long before I purchased the B7100 it has created a groove in the driveshaft cover from the bar, as the cover was hanging down.
IMG_5082D.JPG


After putting it all back together, I gave it a test spin and the driveshaft cover was wobbling,

Driveshaft cover wobbling video

So I pulled it out again and put the driveshaft back in without the cover, in the below video you can see the driveshaft wobbling.

Driveshaft wobbling video

I then seemed to have narrowed it down to the front yoke where it joins onto the splines of the shaft for the front diff, it sort of hinges on the roll pin, and also the front yoke to the front drive shaft splines.

Driveshaft front yoke wobbling

Is this driveshaft wobble something I should be worried about? Or is it normal for the B7100 and how old they are?

It took me awhile to figure out which way to phase the yokes, the parts diagram seems to have them at 90 degrees. I ended up going with 90 degrees, I did test both at the same phase and 90 degrees and the both wobbled the same.

I can see how that amount of wobble would stress the rubber boot which holds the cover from spinning.
 
Last edited:

Lil Foot

Well-known member
Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,578
2,636
113
Peoria, AZ
Wow! What a great looking tractor! That is great to hear! Where did you get the exhaust extension from? Do you ever find it gets in the way of anything?
Thanks!
Here is an earlier post about the stack:
It sometimes catches on low hanging branches, but no more than the ROPs does.

Pic of the second brace- maybe not needed, but it was easy, and nothing vibrates.
IMG_0254.jpg
 
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IdahoNative

Active member

Equipment
Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
118
46
28
Florida, central
I think your leak at the missing bolt between the “bell housing” and engine block is the rear main seal. The bell housing is supposed to be “dry”. It has an inspection port with a removable rubber stopper and a drain bolt on the bottom. A gasket is used between the matting surfaces too.

I bought my well used B7100D with FEL a few months ago for $4300 US. I am in another $1000 for clutch kit, hydraulic controller, hoses, full gasket kit, fluids, etc. After flushing & replacing fluids, the clutch exploded after about 16 hours! After splitting the tractor, I decided to pull the motor. It was puking out excessive amounts of unburnt fuel and just didn’t run right. Cleaned the build-up on the valves, installed new stem seals, cleaned piston tops, checked cylinder liner walls, replaced several gaskets, painted the engine, etc. BUT…after completing everything, the clutch would not disengage! That’s when I learned to buy OEM Kubota parts!

Another member, Kenonf (among several others) offered great advice. Turns out he is about an hour away. I bought a complete rear half from him. It is in much better condition than mine. I just finished the swap and ready to put the clutch together. I hope to be tractoring soon!
 

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Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
I think your leak at the missing bolt between the “bell housing” and engine block is the rear main seal. The bell housing is supposed to be “dry”. It has an inspection port with a removable rubber stopper and a drain bolt on the bottom. A gasket is used between the matting surfaces too.

I bought my well used B7100D with FEL a few months ago for $4300 US. I am in another $1000 for clutch kit, hydraulic controller, hoses, full gasket kit, fluids, etc. After flushing & replacing fluids, the clutch exploded after about 16 hours! After splitting the tractor, I decided to pull the motor. It was puking out excessive amounts of unburnt fuel and just didn’t run right. Cleaned the build-up on the valves, installed new stem seals, cleaned piston tops, checked cylinder liner walls, replaced several gaskets, painted the engine, etc. BUT…after completing everything, the clutch would not disengage! That’s when I learned to buy OEM Kubota parts!

Another member, Kenonf (among several others) offered great advice. Turns out he is about an hour away. I bought a complete rear half from him. It is in much better condition than mine. I just finished the swap and ready to put the clutch together. I hope to be tractoring soon!
Thanks for your reply and sharing your progress

What you are saying makes sense, I wonder if the bolt was removed to allow the oil to escape? How can I investigate further to see if oil is leaking from the main seal? Would I need to split the tractor? If it is the main seal how hard is it to replace?

Gosh sounds like you have been on a bit of a journey with your B7100 but sounds like you will have a pretty much brand new tractor when you are finished :) I am not sure I have the skills to do everything you have done.
 

IdahoNative

Active member

Equipment
Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
118
46
28
Florida, central
Thanks for your reply and sharing your progress

What you are saying makes sense, I wonder if the bolt was removed to allow the oil to escape? How can I investigate further to see if oil is leaking from the main seal? Would I need to split the tractor? If it is the main seal how hard is it to replace?

Gosh sounds like you have been on a bit of a journey with your B7100 but sounds like you will have a pretty much brand new tractor when you are finished :) I am not sure I have the skills to do everything you have done.
To replace the rear main seal, the motor will need pulled or the tractor split and flywheel removed. If it is motor oil, IMO it’s definitely the rear main. If it’s a slow leak, I would not mess with it, unless you have other reasons to pull motor or split the tractor. You can try diesel approved stop-leak, but it never works for me. Just remember to check oil level every time you start it. If you ever remove the flywheel, follow the workshop manual.

It has been a journey. Getting old though, more time working on it than operating it. One thing just kept leading to another. Other than the man-handling, it hasn’t been too difficult. You can certainly do it too…that’s how you better your skills…keep asking questions, follow the manual, study online parts diagrams, take a lot of pre work photos, and whenever possible, buy OEM Kubota parts. Aftermarket parts are the reason I had to split my tractor a second time.

keep us posted!
 
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Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
To replace the rear main seal, the motor will need pulled or the tractor split and flywheel removed. If it is motor oil, IMO it’s definitely the rear main. If it’s a slow leak, I would not mess with it, unless you have other reasons to pull motor or split the tractor. You can try diesel approved stop-leak, but it never works for me. Just remember to check oil level every time you start it. If you ever remove the flywheel, follow the workshop manual.

It has been a journey. Getting old though, more time working on it than operating it. One thing just kept leading to another. Other than the man-handling, it hasn’t been too difficult. You can certainly do it too…that’s how you better your skills…keep asking questions, follow the manual, study online parts diagrams, take a lot of pre work photos, and whenever possible, buy OEM Kubota parts. Aftermarket parts are the reason I had to split my tractor a second time.

keep us posted!
That sounds like a bit of a big Job for me, so as you said maybe leave it for now and if it gets worse try some stop leak, ass you said you never know though and you can keep learning new skills, I have learnt so much already, thanks to everyone helping me. Thanks for the vote of confidence your positivity is great! Hopefully you can start spending more time in the seat when yours is all done.

Yesterday I removed the drain plug from the bell housing, no oil came out, which is a good thing I hope? However the hole was blocked on the inside so I gently stuck a screw driver in and something was blocking the hole but it moved and the screw driver could go in. When I pulled the screwdriver back out though it was covered in tiny dryish black stuff (I suspected metal shavings covered in old oil) that was also magnetic and I didn't have a magnetic screw driver. The clutch seems to work just though, so hopefully nothing to worry about?

I also tried to pull the rubber inspection plug on the side of the bell housing near the hydraulic block but it was really stuck and the edges of the rubber started fulling apart so I stopped.

@IdahoNative do you know much about the front drive shaft? does yours wobble much? Mine seems to wobble due to play in the splines.
Are you able to look at the videos in my post number 46 above and let me know if it is something I should be worried about?
 

Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
The other day I gave the B7100 its first bath, mainly so I could see if there was any oil leaks.
IMG_5053.JPG

Yesterday after putting the front drive shaft back in, I went for a bit of a drive and the 4wd seems to work alright even though the front drive shaft wobbles pretty bad. Hopefully it lasts.

I then serviced the mower deck. I removed all the wheels and old grease etc, cleaned it all the best I could, re set the blade spacing and torqued to spec, well spec of the RC60-71B as I am yet to get the RC60-71H manual. Getting the new gear box oil in was a nightmare, the hole is so small and on the side of the gearbox.

IMG_5090.JPG

The deck is missing some shrouding underneath, maybe one day I will try to weld a new one to help with the grass flow. Although I wont be using the deck much when I get a 3 point rotary cutter.
IMG_5091D.JPG


I then put the deck on the B7100 for the first time since owning it (I had to take it off for transport when I bought it)
IMG_5093D.JPG

My plan next is to take it for a good run with the mower deck cutting grass, then if there is no issues do a full services, of all the filters and fluids. My theory is if it works good as is and no issues, it can only get better with a service, that way I wont be wasting money on a service if there is issues. I have checked all the fluids and they don't look too bad.
 
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Lil Foot

Well-known member
Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,578
2,636
113
Peoria, AZ
do you know much about the front drive shaft? does yours wobble much? Mine seems to wobble due to play in the splines.
Mine has none of that wobble, at either end.
 
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IdahoNative

Active member

Equipment
Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
118
46
28
Florida, central
That sounds like a bit of a big Job for me, so as you said maybe leave it for now and if it gets worse try some stop leak, ass you said you never know though and you can keep learning new skills, I have learnt so much already, thanks to everyone helping me. Thanks for the vote of confidence your positivity is great! Hopefully you can start spending more time in the seat when yours is all done.

Yesterday I removed the drain plug from the bell housing, no oil came out, which is a good thing I hope? However the hole was blocked on the inside so I gently stuck a screw driver in and something was blocking the hole but it moved and the screw driver could go in. When I pulled the screwdriver back out though it was covered in tiny dryish black stuff (I suspected metal shavings covered in old oil) that was also magnetic and I didn't have a magnetic screw driver. The clutch seems to work just though, so hopefully nothing to worry about?

I also tried to pull the rubber inspection plug on the side of the bell housing near the hydraulic block but it was really stuck and the edges of the rubber started fulling apart so I stopped.

@IdahoNative do you know much about the front drive shaft? does yours wobble much? Mine seems to wobble due to play in the splines.
Are you able to look at the videos in my post number 46 above and let me know if it is something I should be worried about?
Dry black stuff: probably dust from the clutch disk wearing. I wouldn’t be too concerned.
Rubber stopper: I had to cut mine out. I plan on using good duct tape to cover the hole, and remove the drain plug so water doesn’t get trapped in the bellhousing.
Front wobble: the video won’t load for me. Keep in mind the front axle does “wobble” as a unit. It’s held in place by one pin at the center, hence the wobble. If you jack the front end up, under the motor, you will see how the entire axle wobbles about the pin.
Edit: I read your questions again. My front shaft does have play in it. Looks like that’s how it was designed, IMO.
 
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Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
Dry black stuff: probably dust from the clutch disk wearing. I wouldn’t be too concerned.
Rubber stopper: I had to cut mine out. I plan on using good duct tape to cover the hole, and remove the drain plug so water doesn’t get trapped in the bellhousing.
Front wobble: the video won’t load for me. Keep in mind the front axle does “wobble” as a unit. It’s held in place by one pin at the center, hence the wobble. If you jack the front end up, under the motor, you will see how the entire axle wobbles about the pin.
Edit: I read your questions again. My front shaft does have play in it. Looks like that’s how it was designed, IMO.
Thanks for your reply, great info and put my mind at rest about the clutch dust and cutting the rubber out.

So your front drive shaft (4WD shaft going from the rear to the front wheels) wobbles too? Strange the videos didnt load they are just on YouTube
 

IdahoNative

Active member

Equipment
Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
118
46
28
Florida, central
Thanks for your reply, great info and put my mind at rest about the clutch dust and cutting the rubber out.

So your front drive shaft (4WD shaft going from the rear to the front wheels) wobbles too? Strange the videos didnt load they are just on YouTube
Yes, right at the rear end of the front drive shaft, where the shaft below the bell housing slides into. I think it’s designed to have some play at this location.
 

Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
I mentioned in a previous post when I got the B7100, the driveshaft cover was spinning with the shaft. The boot is not in the best condition and needs replacing (yet to replace). I finally got a chance to put the front drive shaft back in and tapped up the rubber boot to make it last a bit longer.

I think the cover was spinning for so long before I purchased the B7100 it has created a groove in the driveshaft cover from the bar, as the cover was hanging down.
View attachment 86092

After putting it all back together, I gave it a test spin and the driveshaft cover was wobbling,

Driveshaft cover wobbling video

So I pulled it out again and put the driveshaft back in without the cover, in the below video you can see the driveshaft wobbling.

Driveshaft wobbling video

I then seemed to have narrowed it down to the front yoke where it joins onto the splines of the shaft for the front diff, it sort of hinges on the roll pin, and also the front yoke to the front drive shaft splines.

Driveshaft front yoke wobbling

Is this driveshaft wobble something I should be worried about? Or is it normal for the B7100 and how old they are?

It took me awhile to figure out which way to phase the yokes, the parts diagram seems to have them at 90 degrees. I ended up going with 90 degrees, I did test both at the same phase and 90 degrees and the both wobbled the same.

I can see how that amount of wobble would stress the rubber boot which holds the cover from spinning.
Over the weekend I took my driveshaft, uni/yokes off. I took them to a wreckers and was able to try my yokes on another driveshaft and they wobbled. I also was able to try other second hand yokes on my driveshaft and they only wobbled a tiny bit and they didn't wobble on their driveshaft.

So it seems my yoke splines are definitely worn and my driveshaft splines are only a tiny bit worn. I am going to try and source a replacement yoke to try on my HST output and front diff input splines
 

Whit

Member

Equipment
B7100HST
Aug 16, 2022
60
9
8
Australia
I have done a full services on the B7100, looked like the hydraulic oil had lots of water in it, it is all running pretty good. However since replacing the hydraulic oil the 3 point hitch does not stay up and it creeps down within 30 seconds of raising it up, which is very frustrating when using 3 point attachments. I have ordered new seals for the 3 point cylinder. Will this fix the problem does anyone know?
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
30,552
6,600
113
Sandpoint, ID
I have done a full services on the B7100, looked like the hydraulic oil had lots of water in it, it is all running pretty good. However since replacing the hydraulic oil the 3 point hitch does not stay up and it creeps down within 30 seconds of raising it up, which is very frustrating when using 3 point attachments. I have ordered new seals for the 3 point cylinder. Will this fix the problem does anyone know?
Depends if the issue is in the cylinder or the control valve.
 
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