overriding clutch

[Kytim]

Morning,
when did internal overriding clutches become standard on early "B" model tractors? being as I'm new to the orange, i may need to know this tidbit of information. I would hate to damage a crank or tranny by being being careless. If a clutch is needed, any special knowledge needed when shortening the drive shaft? you know minimum contact length in inches for less than 20HP. Yes I do own a GM B7001 with only 1 groove on the output shaft, what does that tell me? don't newer models have 2 grooves?

Thx for all the info, all my years experience with 40's "red" tractors doesn't apply with these wonderful little machines.

tim

 

[RDR]

With the engine off engage the pto. If it turns one way and you hear a sound like a ratchet and locks the other way I would say you have the internal override. I've mowed with an old tractor for 16 years without one. It isn't that hard to pay attention where I am going and not have to stop on a dime. I like the pto to stop when I stop the tractor.

 

[eserv]

Hi RDR
There is no substitute for a little common sense is there? That being said though, for some people we cannot make the machines safe enough! an overrunning clutch is a good thing to have but if you don't have one and understand the mechanics, you will get along fine. If you have an external one it is liable to give more trouble than the tractor will without one.
Ed

 

[Lucky]

O.K. I am hoping for a final verdict here. It appears my 1979 B7100 doesn't have an overrunning clutch. So is it worth the $50 to pick one up from Fleet Farm. With the tractor off and PTO engaged, I can turn the PTO one way and not the other, but no clicking. Thanks in advance.

 

[Lucky]

Thanks Vic for the last word. I'm going to pick one up.

 

[eserv]

Hi Lucky
It sounds to me like your tractor DOES have an overrunning clutch. If you engage the PTO with the engine off and you didn't have overrunning you wouldn't be able to turn the shaft either way without turning the engine.

 

[Lucky]

With the PTO engaged, I am able to turn the shaft clockwise (turns smoothly), but not counterclockwise. When the PTO is not engaged, I am able to turn it either way. I have checked all the posts on this, and it just confuses me to no heck. I just want to make sure I have the right set up when I use the 4ft bush hog I purchased used this winter.

 

[eserv]

Hi Lucky
The whole purpose of the overrunning clutch is so the PTO impliment can continue to rotate without actually driving the tractor. If you can turn the PTO shaft clockwise when it is engaged without turning the engine you HAVE an overunning clutch. My parts book says you should have one.

 

[Lucky]

Thanks for clearing that up for me. Your help is greatly appreciated!!

 

[asbug]

Spend the bucks and get the external over running assembly.

Vic,
I went to get one from my local tractor place and they only had ones that needed a roll pin installed through the OEM PTO. My PTO is short and doesn't have a hole on the end.
Do you have a make or model of an external PTO overider that will fit my '77 B7001? Thanks,
KC

 

[RDR]

Before you by one, hook the mower up, put the pto in gear, tractor in gear and start down the driveway. Push the clutch in. If the tractor stops and the mower doesn't, you have the overrun in the tractor. If it doesn't stop, the mower keeps pushing the tractor, keep checking around. They make a quick disconnect, you just have to find it.

 

[asbug]

Before you by one, hook the mower up, put the pto in gear, tractor in gear and start down the driveway. Push the clutch in. If the tractor stops and the mower doesn't, you have the overrun in the tractor. If it doesn't stop, the mower keeps pushing the tractor, keep checking around. They make a quick disconnect, you just have to find it.

I have mown with the tractor and when you put the clutch in it will get pushed by the mower. The shaft will not turn in either direction with the PTO enguaged and the motor is off.

I am going to be mowing a pretty good hill, and would like to not have it push me.
Any one know of a good one to get?
Like I stated the big box tractor store has only the 1 type that uses a roll pin to hold on the clutch housing... I remember that my old T-020 had one with a set screw that held the inner housing to the PTO shaft.

Any and all help is appreciated!
Thanks,
KC

 

[stuart]

Just to confirm a technical matter about these smaller tractors.

The preference would seem to be for tractors that had separate clutches for the drive and the PTO. It looks like none of the smaller units have this. This feature is common on mowers, where there is an electric clutch for the mower deck.

An alternative was to have a two stage clutch, that would engage or disengage the implement, then the drive. I also do not see this on the smaller units.

This would mean that, without the overriding clutch, the implement and drive are 'hard' linked to each other whenever the PTO selector in engaged, so the implement (mower) can always drive the tractor for a bit if it has enough rotational energy in the blades.

On a related note, the 'slip clutch' (or shear pin) on the mower is a separate entity from the overriding clutch.

Have I got this correct?

 

[Piker]

Hi Lucky
The whole purpose of the overrunning clutch is so the PTO impliment can continue to rotate without actually driving the tractor. If you can turn the PTO shaft clockwise when it is engaged without turning the engine you HAVE an overunning clutch. My parts book says you should have one.

My 1980 B7100 works as you say - PTO engaged, can't turn the shaft CCW, but can rotate CW easily.

 

[gktilton]

Stuard, the overriding clutch is to keep an attachment from forcing your engine to turn. An example is my brother who runs a 6ft bushhog behind his 13hp tractor, without the overrunning clutch he could reduce the fuel to the tractor down to what should be an idle and the weight of the spinning disc on the thing would keep his RPM's up until it slowed to match. On my B7100, the engine can slow before the attachment hitched to the PTO.

The Slip Clutch is to save you on shear pins so that when you hit a rock with the Tiller and hit binds up solid, the "CLUTCH" can slip or the PIN can shear, but you don't have to CRY because of a huge repair bill.

 

[stuart]

Thanks for the reply. Now, it opens up another question for me.

A 6' brush cutter seems a bit big for 13hp - Does this work ok for him? or tend to stall out in thicker grass? Used 5' and 6' tend to go for less than the smaller ones, as the smaller ones are used to mow between crop rows, and tend to be really beat up before they are replaced.

 

[gktilton]

It is horrible to watch him use this. I tried it on my B7100 which is 16hp and it felt like too much weight and I was never able to use anything higher than 1st gear.

It's what he's got and he makes it work, but not its not enough tractor and not enough HP to do it. He has a small orchard that he inherited from his Father-In-Law and he uses it to clean it up. Really just mowing the grass once a month and uses the hog so he doesn't kill his riding mower on the roots and branches that fall. Most grass doesn't get tall as the trees block most of the light.

Good luck.

 

[asbug]

Called one of the non big box tractor stores and they had one that snaps into the lock groove on my PTO, and that holds on the overrider clutch assembly.
I am going price shop some more, but they were wanting $109.00 US for it.
WOW.
KC