B7100 PTO Overrun Clutch

[TxRzrBk]

I own an early B7100 (sold in 1977) that lacks a integrate overrun clutch. I recently purchased a clutch but I am having trouble making it work on my application. The problem I am having is on the male end of the clutch, the groove for the retainer bolt is in a different location. On my tractor the groove is approximately 5/8" from the end of the shaft, on the clutch the groove is approximately 1 1/8" from the end. On my brush mower the yoke does not have enough depth on the female end that connects to the tractor to reach the retainer groove on the clutch. You will see in the attached pictures that the yoke on the PTO shaft has stops that prevent the male end of the clutch from going deep enough to insert the retainer bolt. Have I purchased the wrong clutch or is there some way I could make it work?

 

[lsmurphy]

Put a clutch on the implement, not the tractor.

 

[kubotasam]

The problem is you have a non standard length on the female pto shaft yoke on your mower. It must have been specifically made to fit the non standard length of the male PTO stub on your tractor. One of my B7100's has that same short shaft. I have read what they were designed, for but I forget right now. I use an over-running clutch on my tractor but the shaft on my finish mower is designed to fit the standard length PTO stub like the male end of your clutch. One option would be to cut the male stub shaft of the over-running clutch to the length of the male end on the tractor.(I don't think I would take this route but it would work) Another option is to replace the female yoke end or the complete PTO shaft on the mower. A third option is to have a second grove machined on the male stub shaft of the over-running clutch. I could do this on my lathe very easily. I think this is the route I would take.

 

[North Idaho Wolfman]

Check the free rotation, you might have it backwards, if it free spins(in the direction you need to power it, clockwise( turn the overrun counter clockwise), and locks in the opposite direction, counter clockwise (turn the overrun clockwise).

There is other models that should fit, onto your tractor.

 

[kubotasam]

The problem is not with the tractor or the over-running clutch. It is actually a non-standard depth of the female end of the pto shaft from the mower. Some B7100's came with a very short (not standard length) male end pto stub on the back of the tractor. He has a female pto shaft end from his mower only designed to fit the shorter length male shaft on the tractor.

 

[TxRzrBk]

Thanks for the replies.
I don't have access to a lathe but maybe I can find a machine shop that would do it at a reasonable rate. The other thing I thought about was using a dremel to grind off the stops inside the female end of the PTO shaft. I hesitated to do this because I thought there might have been a good reason for them being there but if I understand correctly that isn't necessarily the case. Any thoughts on this option?

 

[lsmurphy]

Now I see more clearly.

The clutch is mounted to the tractor......and that's all good.......correct?

The problem is the end yoke on the DS......correct?


Go to NAPA or TSC......>>NAPA can order from Weasler if they do not stock.

Pay the $22 for a new yoke that does fit......swap it and call it a day.....

 

[lsmurphy]

http://www.agrisupply.com/yoke/p/31373/

$22.95

 

[lsmurphy]

Or take an angle grinder with a cut-off wheel and cut the male stub short enough to get the existing coupler on. Start the tractor, engage the PTO, use grinding disc to bevel the stub back to shape.

That will cost you nothing.

 

[North Idaho Wolfman]

I would grind out the stops in the yoke or get a new yoke.

 

[lsmurphy]

Before he grinds out the stops, he needs to make sure the mail stub will not hit the Ujoint, that is why the stops are there.

 

[TxRzrBk]

The clutch is mounted to the tractor......and that's all good.......correct?
The problem is the end yoke on the DS......correct?

Yes and Yes

Or take an angle grinder with a cut-off wheel and cut the male stub short enough to get the existing coupler on. Start the tractor, engage the PTO, use grinding disc to bevel the stub back to shape.
That will cost you nothing.

I like the no cost approach but I feel like I would probably butcher the thing going at it free handed with a grinder. Still might consider this option though

Before he grinds out the stops, he needs to make sure the mail stub will not hit the Ujoint, that is why the stops are there.

If you look at the original pictures I posted you can see the overall length of the yoke. The front edge of the retainer groove on the male end of the clutch shaft is 1 1/8" back. From my view it looks like the shaft would be maybe 1/8" beyond the female end of the yoke which doesn't look like it would cause a problem. Anyone see it differently?

 

[kubotasam]

I wonder if what you are seeing as stops is a build up of dirt, rust , crud ect and the yoke just needs to be cleaned out real good. From your last picture is sure looks like a normal one. Or it could be the end that has been used is worn for an easy fit and further down inside is just a tight fit.

 

[North Idaho Wolfman]

I wonder if what you are seeing as stops is a build up of dirt, rust , crud ect and the yoke just needs to be cleaned out real good. From your last picture is sure looks like a normal one. Or it could be the end that has been used is worn for an easy fit and further down inside is just a tight fit.

Good point, I've seen that too.
But if there is stops your depth looks good.

 

[TxRzrBk]

I wonder if what you are seeing as stops is a build up of dirt, rust , crud ect and the yoke just needs to be cleaned out real good. From your last picture is sure looks like a normal one. Or it could be the end that has been used is worn for an easy fit and further down inside is just a tight fit.

I cleaned it up a little and took another picture, there are definitely stops in the yoke. The other thing I noticed is that the splines widen just beyond the stops, you should be able to see that in the picture also. It looks like the change in the spline width beyond the stops will prevent the yoke from working.

 

[North Idaho Wolfman]

I think it more of a case of the yoke being worn before the stops!
But save any abuse and get a new yoke, If you have trouble finding one I can get you one quick, our local big R store as several in stock.

 

[lsmurphy]

Something there doesn't look right.......if you wiggle it back and forth will it go on now that it is clean?

 

[North Idaho Wolfman]

I agree with lsmurphy,
The valleys and ridges on a PTO shaft are the same size, So the back of the yoke is good and the front of the yoke is worn way out of spec.
That's why it looks like there are stops on it, the "stops" are just non wear spots where the shaft slot hits the inside of the yoke.

 

[kubotasam]

I agree. I also think it is just wear on the splines. You might be able to smooth the transition from the worn to the not worn with a file and get away with using it for a while. However I think it is time for a new yoke. Measure the universal joint carefully, there are many different sizes.

 

[lsmurphy]

I agree. I also think it is just wear on the splines. You might be able to smooth the transition from the worn to the not worn with a file and get away with using it for a while. However I think it is time for a new yoke. Measure the universal joint carefully, there are many different sizes.

Yeah, that thing has future fail all over it.