Kubota B6000E front PTO flange and shaft to clutch

[Berniew]

Hello all. I am attempting to fix the front PTO shaft that drives a belly mower. The owner got fed up with the shear pin snapping everytime he hit something so welded the shaft up. The result is that the shaft broke and is now lost. I have scoured the web to find diagrams or pictures but I still have no idea what it originally looked like or which bits have been modified. I would very much appreciate it if anyone has any diagrams or pictures that would relate to the model I am working on and any advice as to what to do and where to obtain any parts required. The clutch shaft that goes back to the engine should have splines on it where it enters the UJ but they are all worn off. From the UJ to the flange on the end of the crankshaft the shaft is missing. The flange also looks as if it may have been altered. I will try to add some pictures. Thanking you in anticipation of your help. Bernie

 

[Dave_eng]

That front drive setup was used by early B series tractors. Both for a belly mower and a front snow blower.

Often this hardware was used to drive an auxiliary hydraulic pump for things like a loader.

Contact forum member 007kubotaguy using the envelop symbol at top right of most forum pages.
He is often parting out older Kubota's
If you are unsuccessful, a good machinist could put the drive system back together with another universal or flex joint.
Here is more info I found:

I can find #20 part #76251-31550 on line.

Finally I found the complete front drive kit for a mid mount mower on Messicks

Here is a link to the Messick page:

Messicks
Dave

 

[Berniew]

That front drive setup was used by early B series tractors. Both for a belly mower and a front snow blower.

Often this hardware was used to drive an auxiliary hydraulic pump for things like a loader.

Contact forum member 007kubotaguy using the envelop symbol at top right of most forum pages.
He is often parting out older Kubota's
If you are unsuccessful, a good machinist could put the drive system back together with another universal or flex joint.
Here is more info I found:

View attachment 100161

View attachment 100162

I can find #20 part #76251-31550 on line.

Finally I found the complete front drive kit for a mid mount mower on Messicks
View attachment 100164

Here is a link to the Messick page:

Messicks
Dave

Dave, thank you for your time and effort. I will follow both bits of advise. Would it make any difference that my flange has three bolts holding it on to front crankshaft pulley? Bernie

 

[TheOldHokie]

Dave, thank you for your time and effort. I will follow both bits of advise. Would it make any difference that my flange has three bolts holding it on to front crankshaft pulley? Bernie

Those OEM parts are next to impossible to find in any condition let alone servicable. Building a new shaft and takeoff of your own design from scratch is probably the most cost effective solution.

Any way you go you are looking at spending a fair amount of money.

Dan

 

[Berniew]

Those OEM parts are next to impossible to find in any condition let alone servicable. Building a new shaft and takeoff of your own design from scratch is probably the most cost effective solution.

Any way you go you are looking at spending a fair amount of money.

Dan

Thank you Dave. I will approach a local engineering company here in the UK but if cost prohibitive then I still have a small tractor with rear PTO and hydraulics just no front PTO. Bernie

 

[Dave_eng]

Thank you Dave. I will approach a local engineering company here in the UK but if cost prohibitive then I still have a small tractor with rear PTO and hydraulics The bolts wouldno front PTO. Bernie

Bernie
Some of the early B's had splines at the front end of the crank. None of your pictures show the end of the crank with the broken part removed. Could you provide please.

This spine provided a place for a female half to slip over. If this is how yours was originally, two or three securing bolts would make no difference as they just hold the female half of the spline on the male spine on the end of the crank

My sense is that the previous owner's welding work eliminated any flex in the drive which was there to accommodate misalignment. This put severe bending stresses on the shaft each time the engine rotated and lead to the failure.

Go to a small local Kubota dealer with your broken parts and the Messick's parts illustration. One of their mechanics may see a way to get you back in operation.

It is often difficult for those offering advice like me to judge what might be cost prohibitive for you, For some owners just being able to find the parts is a big relief.

The B series are always in demand. Many used ones sell fro more than the original owner paid for them.

Dave

 

[TheOldHokie]

Thank you Dave. I will approach a local engineering company here in the UK but if cost prohibitive then I still have a small tractor with rear PTO and hydraulics just no front PTO. Bernie

I am Dan not Dave

Based on your pictures it looks like you could salvage the front portion that goes into the clutch and couple it to a new custom made shaft and takeoff flange using an off the shelf flexible shaft coupler. If you have enough room for something like this probably better than OEM when done. The coupling is cheap - maybe a couple hundred USD more to make a new crankshaft hub and shaft,

Once properly repaired you might be surprised what its worth on the used market

Dan

 

[Berniew]

be to just to hold the female coupling on ethe cranks male splines.
Bernie
Some of the early B's had splines at the front end of the crank. None of your pictures show the end of the crank with the broken part removed. Could you provide please. This spine provided a place for a female half to slip over. If this is how yours was originally, two or three securing bolts would make no difference

My sense is that the previous owner's welding work eliminated any flex in the drive which was there to accomodate misalignment. This put severe bending stresses on the shaft each time the engine rotated and lead to the failure.

Go to a small local Kubota dealer with your broken parts and the Messick's parts illustration. One of their mechanics may see a way to get you back in operation.

It is often difficult for those offering advice like me to judge what might be cost prohibitive for you, For some owners just being able to find the parts is a big relief.

The B series are always in demand. Many used ones sell fro more than the original owner paid for them.

Dave

Hi Dave, yes the shaft out of the PTO going back into the UJ was splined but that bit got welded up, which i have removed. The welding heat I think dried out the UJ so it probably did twist the shaft off. The shaft coming out of the UJ backwards to the Crankshaft is splined and has twenty teeth on a 10/16th of an inch shaft. I think there would have been a splined shaft going into the flange on the Cranckshaft but that appears to have been welded also as you can see on the back view on photo. I cannot show a picture of female flange with splined internal for drive shaft to come off. I have attached a few more that might help. Thank you Dave. All the best Bernie

 

[Berniew]

I am Dan not Dave

Based on your pictures it looks like you could salvage the front portion that goes into the clutch and couple it to a new custom made shaft and takeoff flange using an off the shelf flexible shaft coupler. If you have enough room for something like this probably better than OEM when done. The coupling is cheap - maybe a couple hundred USD more to make a new crankshaft hub and shaft,

Once properly repaired you might be surprised what its worth on the used market

Dan

View attachment 100193

I am so sorry Dan. I have posted a few more pictures. I am unaware of this type of coupling, how does it work and where can they be obtained from. Do have a look at the mess of things from my recent photos as they may show that this option won't be possible. Thank you for your time and effort and again sorry for getting your name wrong. All the best Bernie

 

[Berniew]

I am so sorry Dan. I have posted a few more pictures. I am unaware of this type of coupling, how does it work and where can they be obtained from. Do have a look at the mess of things from my recent photos as they may show that this option won't be possible. Thank you for your time and effort and again sorry for getting your name wrong. All the best Bernie

Dan, WOW. I have just explored Flexible shaft couplers and they look like just the thing I could use, at a price that I can afford also. Thank you for advise. I'm off to explore couplers and to see if i can find some that will fit. All the best Bernie

 

[TheOldHokie]

Hi Dave, yes the shaft out of the PTO going back into the UJ was splined but that bit got welded up, which i have removed. The welding heat I think dried out the UJ so it probably did twist the shaft off. The shaft coming out of the UJ backwards to the Crankshaft is splined and has twenty teeth on a 10/16th of an inch shaft. I think there would have been a splined shaft going into the flange on the Cranckshaft but that appears to have been welded also as you can see on the back view on photo. I cannot show a picture of female flange with splined internal for drive shaft to come off. I have attached a few more that might help. Thank you Dave. All the best Bernie

That really does not matter if you simply build new from scratch. I believe that particular OEM hub bolted to the crankshaft and had a male splined stub for a flex coupler. I have one on my B7200.

All you need do is replicate that hub using new off the shelf components. You don't need splines - a keyed shaft will work just fine. Here is another style coupler that Ford used extensively. You could fabricate a new hub and bolt the coupler directly to the crankshaft pulley to put the flex point back there. Then use a solid shaft forward to the clutch. I think you will find the center hub on the clutch accepts a tapered and keyed shaft so you are probably ahead to to salvage that broken off end and add an extension to it.

Dan

 

[TheOldHokie]

Dan, WOW. I have just explored Flexible shaft couplers and they look like just the thing I could use, at a price that I can afford also. Thank you for advise. I'm off to explore couplers and to see if i can find some that will fit. All the best Bernie

Its easy to get names mixed up on the forum.

I have built plenty of front PTO takeoffs mainly for hydraulic pumps and there are many affordable options that could be repurposed for your Kubota. If I had that here in the shop it would be pretty easy to do. Kubota loved the splines but that is a real PITA for a machine shop to deal with. Heres another splined hub used by Ford. Hub and matching splined shaft would run you $75. Ford part num,bers 194354 and 192160. Make an adpater plate for the Kubota crankshaft pulley and you have a solid and reliable takeoff point for a flex coupler going to the OEM stub in the clutch

Dan

 

[Berniew]

That really does not matter if you simply build new from scratch. I believe that particular OEM hub bolted to the crankshaft and had a male splined stub for a flex coupler. I have one on my B7200.

All you need do is replicate that hub using new off the shelf components. You don't need splines - a keyed shaft will work just fine. Here is another style coupler that Ford used extensively. You could fabricate a new hub and bolt the coupler directly to the crankshaft pulley to put the flex point back there. Then use a solid shaft forward to the clutch. I think you will find the center hub on the clutch accepts a tapered and keyed shaft so you are probably ahead to to salvage that broken off end and add an extension to it.

Dan

View attachment 100217

View attachment 100216

Dan, I have just explored eBay couplers and I think you are absolutly correct, I can use a solid coupler from PTO going backwards. Then a shaft into a new UJ and another short shaft into a new off the shelf flange. Thank you all on this Forum, really very helpfull and has me excited to fix this challenge. Thanks Bernie. p.s. I will post again with pictures when I have overcome the challenge.

 

[TheOldHokie]

Dan, I have just explored eBay couplers and I think you are absolutly correct, I can use a solid coupler from PTO going backwards. Then a shaft into a new UJ and another short shaft into a new off the shelf flange. Thank you all on this Forum, really very helpfull and has me excited to fix this challenge. Thanks Bernie. p.s. I will post again with pictures when I have overcome the challenge.

I think you have it figured out. Looking foeward to seeing the execution. Those old front PTOs with electric clutchs are highly sought after.

Dan

 

[Berniew]

Okay you wonderful knowledgable people, I have another challenge for you. From my first picture at the start of this post PTO5.jpg, can anyone tell me which type of mower this is and give me any information about it i.e diagrams. The query comes from the fact that when I undid the bolts from the mower attachment plates, to the front of the chassis, in order to get to the bolts for the front PTO I realised that the only thing holding the mower to the tractor then was a bit of rope at the rear of the mower. My question is what is it supposed to be connected to and how, and also, if the owner kept breaking the shear pins was this because the mower wasn't connected correctly and so its height was set to low? Any help greatfully recieved. Thanks Bernie

 

[Berniew]

Dear all, I promised to update once I had resolved my PTO difficulties. I was fortunate to meet a great guy who had a lathe and he drilled out the old shaft from the crackshaft flange and then milled a new shaft for me as both ends are different sizes. I the welded the new shaft to the previously splined shaft and built up using TIG welding the worn PTO end to the universal joint. The end result is that I now have the pto up and running. Thank you for all your very helpfull advice and setting me on the right path. I have attached a few photos of the now replaced PTO shaft. Cheers Bernie

 

[TheOldHokie]

Dear all, I promised to update once I had resolved my PTO difficulties. I was fortunate to meet a great guy who had a lathe and he drilled out the old shaft from the crackshaft flange and then milled a new shaft for me as both ends are different sizes. I the welded the new shaft to the previously splined shaft and built up using TIG welding the worn PTO end to the universal joint. The end result is that I now have the pto up and running. Thank you for all your very helpfull advice and setting me on the right path. I have attached a few photos of the now replaced PTO shaft. Cheers Bernie

I dont mean to be a Debbie Downer and I wish you the best but how did you true the shaft to the hub on the pulley? If its not running true things are going to fail again pretty quickly.

Dan

 

[Berniew]

I dont mean to be a Debbie Downer and I wish you the best but how did you true the shaft to the hub on the pulley? If its not running true things are going to fail again pretty quickly.

Dan

Hi Dan, glad you asked. We set the shaft up on the lathe and then tack welded till we found it running true, that is straight, We then welded it up. I must confess it took more attempts than I care to mention as when, as you know, you heat soemthing it changes the tension and therefore the angle but I am happy with the end result and it is powering the underbelly mower without any problems. Bernie

 

[Berniew]

Hi Dan, glad you asked. We set the shaft up on the lathe and then tack welded till we found it running true, that is straight, We then welded it up. I must confess it took more attempts than I care to mention as when, as you know, you heat soemthing it changes the tension and therefore the angle but I am happy with the end result and it is powering the underbelly mower without any problems. Bernie

I should also say that we drilled the flange out on the lathe and then reemed the new crackshaft to an interference fit and heated the flange to accept the new shaft. Bernie

 

[TheOldHokie]

I should also say that we drilled the flange out on the lathe and then reemed the new crackshaft to an interference fit and heated the flange to accept the new shaft. Bernie

Yes I have made quite a few front shaft drives and I know how it moves. You can turn, bore, and press fit till the cows come home but it wont come out true.

After numerous failures I settled on welding BEFORE final turning. Rough turn and then after its welded the shaft and hub can be turned to final size between centers. Even then you still get significant runout when mounted on the machine

In rhe end I think its better to skip the welding all together and use some flex couplers.

Dan