4oc Transmission Case

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

4oc Transmission Case

Post by fundytides » Wed Jul 25, 2018 1:27 pm

I am doing some repairs to the left side frame on my crawler so I thought that while the side frame is off, it would be a good time to replace the broken bolts that hold the left foot rest to the transmission. I know that 3/4" long bolts were used originally but wondering how far I can safely drill into the boss on the transmission case to allow me to re-tap the holes. So far I am only working on the front one. I have drilled in about 1/2" and have taped the hole using a regular tap and a bottoming tap. which only gives me about 1/4" of useable thread. The boss is about 1/2" thick but I don't have any idea of the total thickness of the case at this point. I would like to drill another 1/4" so I would end up with at least 1/2" of useable thread but I don't want to end up lubricating my drill with transmission fluid. Any suggestions? I am not sure what I am going tot do about the rear bolt as it is impossible to drill without removing the final drive housing. Maybe try to blow it out with the torch. I don't think there is enough bolt left exposed to weld a nut to but I might try that first. I have heard that a good method in a case like this is to weld a washer to the broken bolt first and then weld a nut to the washer. Anyone ever tried that?
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: 4oc Transmission Case

Post by Lavoy » Thu Jul 26, 2018 7:47 am

Bottoming tap should cut to the bottom of the hole, less than 1/8" as far as loss of depth. You are already as deep as you probably better go. 1/2" long bolt is highly adequate.
Welding washer and nut works great, done it for many years.
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: 4oc Transmission Case

Post by fundytides » Thu Jul 26, 2018 9:21 am

Thanks lavoy. I did drill and tapped just a little deeper and I already picked up some 1/2" long bolts so should be ok. Grandson just graduated welding school so the washer and nut process will be good experience for him. Tried to drill out the broken rivets for the data tag but no luck. Also tried to blow them out with torch but that didn't work either. Guess my data tag will just stay on the shelf. Seems to work ok without it (LOL)
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: 4oc Transmission Case

Post by Lavoy » Thu Jul 26, 2018 12:55 pm

Break the heads off the rivets, and sometimes you can drive them all the way through to the inside.
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: 4oc Transmission Case

Post by fundytides » Thu Jul 26, 2018 3:16 pm

No heads on them. I'll give that a try. Do you know what diameter the are? Thanks
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: 4oc Transmission Case

Post by Lavoy » Sun Jul 29, 2018 1:36 pm

3/32' is what sticks in my head, but only a guess.
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: 4oc Transmission Case

Post by fundytides » Mon Jul 30, 2018 10:12 am

Perfect, Lavoy! Tapped right out using a small punch. Thanks for the great advice.
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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