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Junior Member
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Discussion Starter · #1 ·
Need some help trying to figure out how to disassemble the overrunning clutch on a NH H7320 discbine.

I studied the parts diagram. I took out the item 25 and 26 nut/bolt and the whole clutch assembly pulled off the gearbox input shaft fine. Next I pulled out the Item 7 5/16 bolts holding the pto yoke to the slip clutch assembly (item 6). I was expecting the overruning clutch hubs (items 17, 20, and associated parts to come off with the slip clutch. They didn't. The slip clutch slipped off the outer overrunning clutch hub (item 17) easily. I got to what is shown in the photo below and got stumped.
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So A is the pto yoke. B is the outer hub of the overrruning clutch (item 17). C is the inner hub of the overruning clutch (item 20). The notches in B are what engage with the slip clutch.
So B and C turn freely in both directions without turning A like they are supposed to with the slip clutch removed. B and C are locked together when they are supposed to turn freely in one direction and lock up in the other direction. My dilemma is how to get B/C apart from A so I can work on B/C. Nothing jumps out as obvious and the parts list gives no hints.

Anybody have any suggestions?
 

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Look closely at the end of the hub “B” and you will see a snap ring. The snap ring does not have ears like what you are probably familiar with. Remove the snap ring and all will come apart. You will need a new “B”. When you get the hub off, look for a line cut into the hub. The line will be in between two ramps.

You might want to round the corner slightly of the drive plates on the trailing side, not the side that drives in the ramps
 

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Discussion Starter · #3 ·
Thanks Mike. I saw what I thought might be a snap ring but didn't see the typical ears so I wasn't sure what it was.

It looks to be an internal snap ring? Any tricks to getting it out if it doesn't have the typical ears to squeeze together?

Also, what's the significance of the line in the hub?
 

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The snap ring is external. They make a snap ring pliers for that style. You might try a needle nose pliers in the opening of the snap ring to spread the snap ring to remove it. The line is a groove caused by the square drive plates that somehow cock and dig into the hub. You will only see one and sometimes you have to look closely to see it. Since it is only your time involved, you might try sanding the groove to remove the edges pushed up by the square drive plate and round over the corner of the drive plates so they can not catch again. Only round the corner that is not driving the hub.
 

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Discussion Starter · #5 ·
Thanks for the advice Mike. Spot on as usual.

The needle nose pliers did the trick and the snap ring came right off (after a couple of tries) and the hub came right off the shaft. As you predicted, there was a groove on one of the ramps in the hub. All the other parts appear to be in good shape. Is this groove fixable or does it warrant a new hub?
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I will get at rounding over the one edge on each drive plate before I reassemble. Then I just need to pay attention and put them in to shaft in the right orientation.

Any particular things to watch out for during reassembly? Other than orientation of my modified drive plates, seem pretty straight forward.
 

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Junior Member
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Discussion Starter · #8 ·
Opted to get a new hub. Also took the slip clutch apart. The friction disks were rusted together. So a couple of new friction disks are in order. Found a website of a small company in Ronks, PA that specializes in discbine repairs and parts. New hub (plus the repair kit parts) and two friction disks, with shipping were $183. These are not used parts, although he does sell used parts.

Here is where it gets interesting. Prior I was at a NH dealer's website (that large dealer in eastern PA that lots of people use). The same set of parts there, with shipping would have been about $400.

Pays to shop around for parts.
 
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