Over Running Coupler needed

I keep reading conflicting terminology and info and am trying to get this straight in my head so I don't get myself in trouble. And I'm new to tractors so apologies for a basic question.

I just got a 1971 Massey 175. The PTO on this one has a shifter to the left of the seat that goes from ENGINE to NEUTRAL to GROUND. This is considered a "LIVE" PTO, correct?

In either case, when running a bush hog, do I need to use an Over Running Coupler or Clutch on this tractor? Without one, the PTO does continue spinning after you shift it into neutral. Is this what people are referring to when they say that the continued spinning of the PTO can propel the tractor forward when you're trying to stop?

And if I do need the coupler, the shaft on my bush hog will need to be shortened. Do I trim the male or female end, or does it matter? Any advice on the best way to trim it?

Thanks.

YOU DO NOT need the over running clutch. The PTO is just coasting after you disengage it. The none live PTO would push the tractor while coasting down.

Your tractor just does not have a PTO brake like most new tractors do.

Your tractor has the ability to power the PTO relative to engine speed (the typical way) or relative to the ground speed. There are very few applications that benefit from the ground speed setting so for general work, mowing included, it should be driven relative to the engine.

If the foot clutch disconnects both the ground drive and the PTO drive at the same time you would need an over-running clutch. However, I believe that the 175 had a two-stage clutch when equipped with the option of running the PTO relative to the ground speed. This means that you push the clutch halfway down to stop the transmission and the rest of the way down to stop the PTO. There are actually two clutches in the system, one for the transmission and one for the PTO, that are activated by the same foot pedal. In this case you would not need an over-running clutch since the PTO cannot "back-drive" the transmission.

Yeah, but. I have a Massey Ferguson 240, and the bush-hog spins down real slowly, except for the few times when something happens, and it SLAMS!!! hard and stops. Rocks the tractor. So even tho I don't necessarily need one, I use one. Only costs a little, and protects a great deal.

Sorry I'm being thick here, but with the ORC your blades stop spinning immediately?
And when you say you're using it for safety. . . what negative scenario is it preventing?
Thanks,
Matthew

No, the overrunning clutch lets the brush hog keep spinning. The PTO can drive it but it cannot drive the PTO.

I don't know what he means by "when something happens".

I don't have live PTO and I don't usually use an over running clutch. They are a lot of maintenance and it doesn't push the tractor very far. When I have to stop in a hurry I kick the PTO out as I'm stopping and let the brush hog spin down. A lot of times I can re-engage it before it spins down.

Now I'm confused, and I fully understand an over running coupler.

You guys are already talking about 3 different things..... and kinda in circles.....


Figure out if your tractor has live (or independent) pto. I'm not familiar with your brand....... of it is, there is -no- reason to add one!

If it does not, an over running coupler allows the pto to freewheel (spin on its own) when you push in the clutch.

It works like a socket set ratchet. Power can only be applied in one direction, but not the other direction. So the tractor can power an implement, but the implement can't send power back to the tractor.

An orc doesn't really 'protect' anything, that would be a slip clutch. Totally different topic.


Paul

American Society of Agricultural Engineers definitions: "Live" PTO allows the operator to stop and start the ground travel without interrupting the PTO. "Independent" PTO allows the operator to stop and start the ground travel without interrupting the PTO, AND it allows the operator to start and stop the PTO without interrupting the ground travel. The MF 175 was available with either one. Yours is "Live" PTO. There is also "Transmission" PTO where everything beyond the clutch stops when the clutch is disengaged.

I have to believe that JD is correct, as he probably knows that particular tractor and I do not. If you are new to tractors and equipment, you need to know that the implement will not suddenly stop when you step on the clutch. My Ford 515 has a PTO brake and it will not stop things very quickly. There is a lot of momentum in anything that is being driven. what the overrunning clutch does is let the power be transmitted in the direction to drive the implement, but to slip, or disengage, or let the shafts turn at different speeds, when the clutch is depressed, and the PTO shaft begins to run slower that the implement shaft. On some tractors, notably the 9n, 2n, and 8n Fords, when you step on the brake, the implement will keep pushing the tractor forward while the momentum of the implement winds down, sometimes into a fence post, or tree, or ditch. The over-running clutch prevents it from doing that.

Now I'm confused, and I fully understand an over running coupler.

You guys are already talking about 3 different things..... and kinda in circles.....


Figure out if your tractor has live (or independent) pto. I'm not familiar with your brand....... of it is, there is -no- reason to add one!

If it does not, an over running coupler allows the pto to freewheel (spin on its own) when you push in the clutch.

It works like a socket set ratchet. Power can only be applied in one direction, but not the other direction. So the tractor can power an implement, but the implement can't send power back to the tractor.

An orc doesn't really 'protect' anything, that would be a slip clutch. Totally different topic.


Paul

yes an over running can protect something...some mowers do not have an over running coupler and if that tractor has a pto brake, the mower can and will wear out the pto brake..have 15 ft bat wing with no over running coupler and it will spend a long time after you kick out pto, so I slow engine down and back into heavy grass and I kick out pto to save the brake, so far it has worked..sometimes I kill engine and let it stop..

Do you mean step on the brake or step on the clutch? Thanks