40c sprocket bolts

General help and support for your Lindeman through 2010 John Deere crawler
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fundytides
440 crawler
440 crawler
Posts: 223
Joined: Sun Oct 27, 2013 8:41 am
Location: Saint John, NB, Canada

40c sprocket bolts

Post by fundytides » Thu Dec 26, 2019 9:27 am

Just finished replacing my track and idlers and rebuilding front idler assembly. Thought I would check sprocket bolts as well. One was stripped and others looked seedy so I bought 6 new JD21T from the local JD dealer. Went to install them today and found to my surprise that my bolts are 5/8" but the new ones are only 9/16". Both are fine thread. Checked the bolts on my other sprocket and they are 9/16" like the new ones. Has my axle flange been changed to one taking 5/8" bolts or just enlarged/rethreaded. Do newer crawler's axle flanges (420, 440 etc.) take larger bolts and would they fit on my 4 roller 40? Also, I notice that the new bolts have a tapered "neck" where they fit through the sprocket. My original bolts are not tapered and the holes in the sprockets are not tapered. Any ideas or should I just buy some regular 5/8" fine thread bolts and use those?
have 40c 4 roller crawler, 1927 Ford T Touring car, 1931 Ford A Roadster, 1951 Standard Vanguard Saloon. Never a dull moment!

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Lavoy
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Re: 40c sprocket bolts

Post by Lavoy » Thu Dec 26, 2019 9:37 am

Someone had drilled out your axles to the next larger size. Just use 5/8" fine thread bolts and lock washers, you will be fine. I am assuming that you axles have all 3 dowels still in place.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

fundytides
440 crawler
440 crawler
Posts: 223
Joined: Sun Oct 27, 2013 8:41 am
Location: Saint John, NB, Canada

Re: 40c sprocket bolts

Post by fundytides » Thu Dec 26, 2019 9:46 am

Thanks Lavoy. That's what I will do. Yes studs are all in place. What about the sprocket that has the original 9/16" holes in it? How come the holes aren't tapered to accommodate the JD bolts or are the bolts not tapered originally?
have 40c 4 roller crawler, 1927 Ford T Touring car, 1931 Ford A Roadster, 1951 Standard Vanguard Saloon. Never a dull moment!

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Lavoy
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Re: 40c sprocket bolts

Post by Lavoy » Thu Dec 26, 2019 10:05 am

Under a certain serial number the MC which uses the same sprocket as the 40 used a tapered bolt because there were no dowels in the hub, so they had to have the taper, just like a rim on a car. Later they came out with the doweled hubs because the tapered bolts were just not enough. Evidently they never bothered to change the part number of the sprocket bolts when they changed to the later style hubs. Possibly to make sure no one substituted the later bolt to an early hub.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

fundytides
440 crawler
440 crawler
Posts: 223
Joined: Sun Oct 27, 2013 8:41 am
Location: Saint John, NB, Canada

Re: 40c sprocket bolts

Post by fundytides » Thu Dec 26, 2019 11:34 am

Thanks Lavoy for the quick response. I'll just get the 5/8" bolts
have 40c 4 roller crawler, 1927 Ford T Touring car, 1931 Ford A Roadster, 1951 Standard Vanguard Saloon. Never a dull moment!

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