630 clutch cotter pin revisited

fixerupper

Well-known Member
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OK, I got new cotter pins from Deere, they are soft, they cut easy with the side cutter, but I put them in and buttoned it up. The one thing I picked up on was the end play in the pivot pins. The pins are 3/16" longer than they need to be. I'm thinking these pins are sliding end for end and hammering the cotter pin into submission.

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Here is the last broken cotter pin. It has seen a rough life. The way it is mashed and flared a bit right where it broke at the base of the loop tells me it is being hammered. I don't know if these pivot pins are factory. My hunch is they have been replaced with pins that are too long.
 
Brazing may have fixed your issue? I see a lot play between ears and pivots, this is where the shearing action is coming from. Washers on either side of pivots would reduce this side movement transferred into the pins, but the reason for it is the too wide of a hole repaired now with bronze. A belleville washer behind the cotter key would tend to return a safety amount of room when no longer under tension. I would do both washer suggestions if it's a real concern, but I'm thinking the bronze pretty much has it fixed for the next 40 years. Not so much hammered is my opinion here, more side to side shearing. I agree with carlyle, the ends of the cotter keys need to be in a handlebar mustache form, curled up from either side.
 
No specs, just a part #. Thanks to everyone so far for the suggestions. I don't even pretend to know it all so that's why I ask you guys for help. If you see something I screwed up on by all means let me know. Jim
 
Lee I am going to order new pins if these are too long. I don't have another pin to compare them to. I would think the Deere engineers would have prescribed a pin that did not have 3/16th extra length. Your idea of shimming the rocker dogs is a good idea I never thought of. If I remember right I did replace those rocker pins years ago. I might have ended up with the wrong ones and didn't catch the mistake or maybe I did notice the length difference but didn't think it mattered. What concerns me the most, more than the inconvenience of fixing it all the time, is the possibility of an ear breaking off when a pin is half way out.
 
Just stumbled across your other post so I can see the bronze was not the fix here. Ok, the issue of which direction to put the pin would depend on which side the collar is from the pivots when you engage the clutch. Since this is kinda nebulous in the first place is probably the reason they have extra long pins in there and so much slack between pivots and ears. Direction of rotation not so much important in my opinion as from which side are the dogs being forced into the pivots from. Could easily be from either side depending on where that index hole with the bronze repair lines the collar up at. If you are shearing cotter keys then put the pin in backwards to how you took it out? If it still does it, then you should washer up the pivots and put belleville washer under the cotter key. Be careful the first time you try to engage the clutch after washers put in - it now may be too tight to disengage easily and needing adjustment badly. Try to washer up the pivots such that they appear to be dead square to the dogs.
 
After more thought I still think Deere made it this way on purpose. We are supposed to shim the pivot and having all that room in there allows us to customize the position of it to be dead square which is something mass production can't guarantee very well. Extra length of pin then is just insurance for worst case? My guess is that new pins from proper part number will be exactly the same as you already have and thinking mine are also quite long which I thought odd but used them anyway.

Not a good feeling to know the pins could be caught by one hole only true enough. There must be enough slack in hanging by one hole that it doesn't break the ear, but still not a good thought to have.
 
I'm likely misunderstanding something here but:

-How come that damaged "cotter pin" looks so much like a piece of plain wire bent into the shape of a cotter pin? In the picture I don't see a "flat side" typical of a cotter pin. I'm thinkin that never did look like a cotter. Not even on the day it was first installed.

-How do these pins hammer back and forth enough to pound cotter pins (of any style) to bits? I well understand how all 2 cylinder JD's have increases & decreases in crankshaft speed every crank rotation caused by the engine's firing arrangement. What I dont "get" is even if the clutch dog pins were an inch too long, how can they be bouncing back and forth at all? Here's why I'm puzzled..... When the pulley is rotating with the crankshaft the clutch is in the engaged position. When the clutch is engaged, these pins are under all the force of the toggles as they push on the clutch dogs to squeeze the clutch pack. The mass of these pins is not nearly great enough nor the JD hammering powerful enough to cause these little guys to slide back and forth and hammer the cotters into submission WITH THE CLUTCH ENGAGED!

-For the pins to be free enough to move back and forth in their mounting holes, the clutch has to be in the disengaged position. Problem is the crankshaft pulsations are NOT transferred to the pulley when the clutch is disengaged! That means the hammering forces are not present.

Not trying to jerk any chains here. I'm just not seeing how this 3/16" extra pin length allows these comparatively little pins to hammer back and forth so much that the true cotter pins get pounded to pieces! Not saying it's impossible but I'm thinkin maybe these particular "cotter pins" never were what they're assumed to have been to begin with and that may best describe why they don't look right today!

;-)

That's my pair o pennies on the matter!
 
Seeing your earlier post & how you've been there in the recent past (compared to the tractor's age) I am simply clueless!

I've worked on a lot of A's but never a 630 so I this is just one more thing in the long list of things I don't know.

Wish I was better help.
 
(quoted from post at 16:21:19 08/03/15) I'm likely misunderstanding something here but:

-How come that damaged "cotter pin" looks so much like a piece of plain wire bent into the shape of a cotter pin? In the picture I don't see a "flat side" typical of a cotter pin. I'm thinkin that never did look like a cotter. Not even on the day it was first installed.

-How do these pins hammer back and forth enough to pound cotter pins (of any style) to bits? I well understand how all 2 cylinder JD's have increases & decreases in crankshaft speed every crank rotation caused by the engine's firing arrangement. What I dont "get" is even if the clutch dog pins were an inch too long, how can they be bouncing back and forth at all? Here's why I'm puzzled..... When the pulley is rotating with the crankshaft the clutch is in the engaged position. When the clutch is engaged, these pins are under all the force of the toggles as they push on the clutch dogs to squeeze the clutch pack. The mass of these pins is not nearly great enough nor the JD hammering powerful enough to cause these little guys to slide back and forth and hammer the cotters into submission WITH THE CLUTCH ENGAGED!

-For the pins to be free enough to move back and forth in their mounting holes, the clutch has to be in the disengaged position. Problem is the crankshaft pulsations are NOT transferred to the pulley when the clutch is disengaged! That means the hammering forces are not present.

Not trying to jerk any chains here. I'm just not seeing how this 3/16" extra pin length allows these comparatively little pins to hammer back and forth so much that the true cotter pins get pounded to pieces! Not saying it's impossible but I'm thinkin maybe these particular "cotter pins" never were what they're assumed to have been to begin with and that may best describe why they don't look right today!

;-)

That's my pair o pennies on the matter!

Buckeye your idea makes sense. The pins could not slide end for end with the clutch engaged. Hmmm you have me thinking now but I don't know what to think about. The collar can't wiggle because the hole the centering pin goes through is about the right size to prevent that. Could there be an acceleration of sorts that is doing this right at the beginning of engagement? Acceleration would force the head of the pin against the ear with the pins oriented the way they are. Shearing action on the cotter pins would have to occur from a pivot pin backlash toward the direction of rotation. When is this backlash happening? The fraction of a second when the clutch is disengaged and the collar snaps back? That would lead me to think the pivot pin should be installed the opposite direction from the way I have it. The parts diagram on Deere's website shows the pin orientation the way I have it. The more I think about it, this shearing is happening at the time the clutch is disengaged. The pin in the picture does have a flat like a cotter pin. The picture may not show it.
 
If you know the part# for the pins, check availability on jdparts.com. If they're still available the dimensions should be listed and you can compare the length to the ones you have.
 
Pete I did not see dimensions in the parts book unless there is another section in the parts book I don't know about. All I saw was the part number. I used to have another 630 pulley laying in one of the sheds but I'll be darned if I can find it.
 
The specification drawing at jdparts is showing a special round head rivet pin. 2.500 long and 2.312 to center of cotter pin hole. 3/16 cotter pin per the parts book.

Since you already know they are being hammered to death the way you had them why not try the other way?
 
Just pulled out the John Deere service manual for a 60 for a look see. The pic in it is showing the pin turned the other way.
 
Thanks M Man. Maybe I should flip them. I'll have to dig into JD parts a little farther to find specs. Thanks

Where did you find the specs drawing on Deere's website?
 
When you log in at jdparts and enter the part number in the search box it will bring up a page showing price and availability. At the bottom of that page you'll find the specifications.
 
Looking at your picture looks like the clutch gear has slid out and letting the operating collar move out too far . I think the pins are too long but shouldn't be a problem . Get the right cotter pins and wrap them up . Also I always put the heads so that the impulses would hit the head, in having said that I have put them in both ways with no problems .
 
When I get the time I am going to pull this thing back out and check it over now that I know a little more about it. Seems like I thought the gear was slid out too but when I put the pulley on the tractor the gear meshed in the center of the reduction gear at that time. I'll take another peek at the gear. I can have the pulley out in 15 minutes. I pick that side of the tractor up with the chain hoist, slip a jack stand under it, pull the rear wheel out to the end of the axle and there it is ready to work on.
 

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