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Off Topic Bolt torque specs

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I

ichthos

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This question is way off topic-it is about the wheel bolts on a tractor, but I am still hoping I can get some information. The bolts have a 7 on it. A one inch socket fits the head perfectly. The bolt diameter appears to be between 9/16 and 5/8. I am guessing this is a metric bolt. What does the 7 refer to, and how do you figure out the torque values for this? Any help is appreciated.
Kevin
 
Perhaps this will be of some use for the second half of your question:

https://www.boltdepot.com/fastener-information/bolts/US-Recommended-Torque.aspx

Poking around some I found this: https://www.stealth316.com/2-3s-fastener-tips.htm

RIP:

The head mark is a number molded into the head of the bolt or screw. The marks approximately correspond to the following property classes:
Head Mark "4": 4.6, 4.8, 5.6, 5.8, 6.8
Head Mark "7": 8.8
Head Mark "8": 9.8

That page contains torques by head mark (7) and bolt size. Sounds like you may have an M14 or M16.
 
I assemble compact tractors manufactured in India and South Korea. Geo is correct - you've got 8.8 bolts. We see both M16 (4wd front and rear wheels) and M18 (these are found on 2wd front wheels) using 24mm heads.
We torque the M16 to 145 ft lbs. and the M18 to 251 ft lbs.
Kinda surprised torque specs aren't in your operator's manual.
 
Thanks for the information Geo and Jay. There was conflicting information in my manual, and I could not for the life of me figure out the 7. The manual listed 8.8 bolts but never stated the 7 corresponded to this number. Thought I understood the metric bolts, but I guess I had more to learn-thanks.
kevin
 
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