Kubota 7100 hst trouble.

Robert500

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Hello everybody, got an offer to buy a nice 7100 hst tractor...

The seller have taken the cardan shaft off the tractor because when mounted the tractor whines a whole lot, he says that the whining sound been getting worse and worse in 4wd BUT without it the cardan in the tractor runs just fine ***129300;

Any suggestions on what might cause this?

He says he has not changed any oil or filter as long as he had the tractor.

Looked in the manual to see if I could find something obvius but still confused...

Im going to take a look at the tractor on monday or tuesday so any suggestions what to look for or ask the seller would be appreciated.
 

85Hokie

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Re: Kubota 7100 hst trubble.

If you have the shaft in hand , inspect it front to back.
I am betting something is amiss in the front diffy.

While you are waiting for someone to pin it down......I would change the fluids and filters!!!! That's after you low ball him and buy it !:D What is he asking for it in the condition it is in? Does it have 4 lug front end or 6 lug ?

You have the WSM? There are several online if you need one.
 

D2Cat

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Re: Kubota 7100 hst trubble.

Robert, you say two things that are inconsistent. "a nice 7100 hst tractor... and "He says he has not changed any oil or filter as long as he had the tractor."

It might appear NICE, but if it has been in operation in the original fluids for 30 years (or however long the man has owned it) I would be giving him a low enough figure to cover fluid changes and other unknowns.
 

85Hokie

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Re: Kubota 7100 hst trubble.

"I would be giving him a low enough figure to cover fluid changes and other unknowns."

D2Cat - if this wasnt across the pond..........we would be looking at, would we not???:eek::D:)

Then would have to make the KTA (Kubota Tractor Anonymous) meetings twice a week;)
 

RCW

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Re: Kubota 7100 hst trubble.

It might appear NICE, but if it has been in operation in the original fluids for 30 years (or however long the man has owned it) I would be giving him a low enough figure to cover fluid changes and other unknowns.
Robert - D2Cat and Hokie are both right on, as usual. They're both smart guys that need help with their affliction to tractors.:p

Nice is not defined by appearance with tractors. Maintenance is everything.

The HST is great, but requires some attention/maintenance. The current owner went about that entirely wrong.....

Cat and Hokie - am I correct in saying the HST is as expensive as the engine itself?? Many HST's are simply replaced with new, because it is not economical to rebuild them. What - $4,000 US or so?

But, like Hokie said - if removal of the propeller shaft (the driveshaft to the front differential) helps, then maybe it's a front differential/axle issue - much less money, and could be a more simple fix. Couple that with a routine fluid/filter change, maybe you'd be good to go!

It's entirely possible that if the owner kept up with maintenance, he wouldn't have wanted to take the shaft out in the first place!

Good luck!
 
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D2Cat

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Re: Kubota 7100 hst trubble.

RCW, you inquire...."Cat and Hokie - am I correct in saying the HST is as expensive as the engine itself?? Many HST's are simply replaced with new, because it is not economical to rebuild them. What - $4,000 US or so?"

For proper HST rebuild it is expensive. You have to either transport the machine to Sandpoint, Idaho, or pay air fare and housing for North Idaho Wolfman to your neck of the woods!!:D:D
 

85Hokie

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Re: Kubota 7100 hst trubble.

am I correct in saying the HST is as expensive as the engine itself?? Many HST's are simply replaced with new, because it is not economical to rebuild them. What - $4,000 US or so?



RCW - I betcha I would look for another machine - you are right - those HST costs would almost prohibit getting the machine for .....free!!!!

I hope for the sake of buying that tractor - the front end just needs a little TLC:)
 

North Idaho Wolfman

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Re: Kubota 7100 hst trubble.

For proper HST rebuild it is expensive. You have to either transport the machine to Sandpoint, Idaho, or pay air fare and housing for North Idaho Wolfman to your neck of the woods!!:D:D
Wife say she's totally up for a Swedish vacation! ;)
I hope they like wolves over there! :D
 

Robert500

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Re: Kubota 7100 hst trubble.

Thanks for replys!
To answer some questions, its the 6 lug front end.tractor is made 1988 it seems.
Doesnt it seem strange that the HST would be bad if the tractor works fine and no loud whine with cardan taken off? Could it be a pressure relief valve?

"Something is amiss in the diffy" what does that mean/could that be?
Thanks again / Rob
 

Robert500

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Re: Kubota 7100 hst trubble.

Btw, if the filters and or low/wrong oil in the tractor, could that cause the whining sound?
 

85Hokie

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Re: Kubota 7100 hst trubble.

"Something is amiss in the diffy" what does that mean/could that be?
Thanks again / Rob
Based on what you are describing - the whine occurs while in 4wd is engaged.

DOES it make the noise when 4wd is not engaged? that is - with shaft in place?

I am thinking - and that is dangerous, that you differential in the front is causing the whine. OR the whine is coming from the HST that is trying to push the front end along.

DUMB question - what size tires are on this machine - front and back???? I betcha if those tires are not the correct size - it would make a very bad "whine"

and as for year - look on the plate on the clutch side and read off the serial number ......that when looked up will tell you the "year" of build.

According to the years of manufacturing - there was no HST B7100 sold in the US in the late 80's....but then again - doenst mean you dont have one from that era on that side of the world.

Upload some pictures and check the tires sizes and report back.
 

Lencho

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Re: Kubota 7100 hst trubble.

Will one of you smart fellers tell me -What is a "cardan shaft"? Is it the driveshaft to the front axle? I also have a B7100hst. The hst does whine a little ( lowder in hi range than low) but I think that is normal. My second question for the potential buyer is why not just shift out of four wheel drive into two?
 

Robert500

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Re: Kubota 7100 hst trubble.

Based on what you are describing - the whine occurs while in 4wd is engaged.

DOES it make the noise when 4wd is not engaged? that is - with shaft in place?

Yes ***9757;***127995;***65039; The moment the drive shaft for the front end (that I call cardan shaft) is in place the "bad whining" begins.

I am thinking - and that is dangerous, that you differential in the front is causing the whine. OR the whine is coming from the HST that is trying to push the front end along.
***9757;***127995;***65039; Would be My best case scenario i think...
DUMB question - what size tires are on this machine - front and back???? I betcha if those tires are not the correct size - it would make a very bad "whine"

***9757;***127995;***65039; Looks original.

and as for year - look on the plate on the clutch side and read off the serial number ......that when looked up will tell you the "year" of build.

According to the years of manufacturing - there was no HST B7100 sold in the US in the late 80's....but then again - doenst mean you dont have one from that era on that side of the world.

***9757;***127995;***65039; FairPlay certain that its a 1988 model...
Aaaabbbbaaaabbbbbaaabbbbaabbbbbaabbb
Upload some pictures and check the tires sizes and report back.

msndjdldndkzmsnnsksmssnmsms
 

85Hokie

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Re: Kubota 7100 hst trubble.

Will one of you smart fellers tell me -What is a "cardan shaft"? Is it the driveshaft to the front axle? I also have a B7100hst. The hst does whine a little ( lowder in hi range than low) but I think that is normal. My second question for the potential buyer is why not just shift out of four wheel drive into two?
Len,

you are correct the cardan shaft is a term that is not used as much as it was in the US - drive shaft, pto shaft are more common names.


Cardan shaft is more of a European term named for its inventor
 
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Re: Kubota 7100 hst trubble.

Will one of you smart fellers tell me -What is a "cardan shaft"? Is it the driveshaft to the front axle? I also have a B7100hst. The hst does whine a little ( lowder in hi range than low) but I think that is normal. My second question for the potential buyer is why not just shift out of four wheel drive into two?

The trubble is really about tribbles. If any of those Idaho wolves want to take an exploratory trip to Oregon I'm happy to host as long as they go back home.

Sorry, I love bad puns but the offer is genuine.
 

Lencho

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85hokie - thank you for answering my question about the cardan shaft. I learn something on this forum everyday! It still seems the seller's story is off - I'd want to see how the tractor performs with the driveshaft in place. A B7100 is worth repairing but better to know the status before you buy.
 

85Hokie

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85hokie - thank you for answering my question about the cardan shaft. I learn something on this forum everyday! It still seems the seller's story is off - I'd want to see how the tractor performs with the driveshaft in place. A B7100 is worth repairing but better to know the status before you buy.

Len,

he did say this - "Yes ***9757;***127995;***65039; The moment the drive shaft for the front end (that I call cardan shaft) is in place the "bad whining" begins."

But I am like you - if placed in and the 4WD out of gear......still whine???

Unless the shaft is binding the HST ---- I am lost ....then again clear information is vague:)
 

North Idaho Wolfman

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If it has 6 front lug wheels it could be as new as 85, that was the last year that model was made.

Whine could be hundreds of things on that model, could be "normal hydro whine", I looked at a tractor that a guy swore up and down the Hydrostatic trans was bad because of the noise, turned out to be quite normal.
Also if it has the wrong fluid or filters yes that can cause excessive noise too.

There is a joint that is in the main shaft from the clutch to the transmission and if that joint is bad it too will cause excessive noise.