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Old June 23rd, 2020, 09:26
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5/8 Ubolt torque

Guys what's your best advice for torque on this big of hardware vs 8.25 axle tubes.

Fsm shows 55ftlb, 5/8 bolts upwards of 150-180 pending coarse/fine threads.
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Old June 23rd, 2020, 11:23
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Re: 5/8 Ubolt torque

Go factory?
Or will bolts crush the tube at the 5/8 torque spec?
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Old June 23rd, 2020, 13:01
JonnyCat63 JonnyCat63 is offline
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Re: 5/8 Ubolt torque

I just did the torque on my 8.25 with 9/16" hardware. When I looked for the torque specs, I found all sorts of conflicting information, too. In my research, it seems that the majority of information said to torque the 9/16" u-bolts to about 90 fl/lbs. Most of that info was found online from u-bolt manufacturers, or from shops specializing in springs, etc.

90 seemed reasonable to me, so that's what I went with. From what I remember, you could torque 5/8" a little more. 55 is for the smaller factory bolts, so I wouldn't do that for the 5/8". The most important thing is to check it periodically.
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Old June 23rd, 2020, 13:07
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Re: 5/8 Ubolt torque

Yeah for now I went 100ftlb, just didn't want to under do it and have them wiggle overtime.
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Old June 23rd, 2020, 14:34
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Re: 5/8 Ubolt torque

Torque to the 5/8 spec. I seem to recall for 5/8 it is 130 foot pounds but google may give you different.
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Old June 23rd, 2020, 18:12
srb531 srb531 is offline
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Re: 5/8 Ubolt torque

yes , you can crush the stock tube, cause i did it trying to tighten 9/ 16 u bolts too much. be careful 100 lbs is almost double what the tube is designed to handle.
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Old June 23rd, 2020, 19:09
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Re: 5/8 Ubolt torque

I have been tightening 5/8 ubolts to proper torque for 20 years and not crushed a tube yet.

But if you are uncomfortable doing that, run smaller ubolts. Under torquing is dangerous
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Old June 23rd, 2020, 21:45
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Re: 5/8 Ubolt torque

https://www.almabolt.com/pages/catal...ningtorque.htm

I was looking at this. That seems extreme for its intended purpose. I Imagine it takes hella force to crush an axle tube, but I do want to torque these correctly.
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Old June 23rd, 2020, 21:51
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Re: 5/8 Ubolt torque

Deaver has a chart. I will post it tomorrow. 5/8 grade 8 ubolt is 169. Grade 5 is 130.
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Old June 24th, 2020, 06:50
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Re: 5/8 Ubolt torque



This chart comes [sometimes] attached to Deaver springs. It's what I use to torque.
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Old June 24th, 2020, 07:22
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Re: 5/8 Ubolt torque

I assume ruffstuff ubolt are grade 8, but holy hell thats some serious torque for a U bolt. More than tripple the stock bolts, at what point would one worry about this damaging the axle housing?

In my mind ide think a bigger bolt could just handle more clamping force.
Would a bigger ubolt not hold the same as a smaller ubolt at the same stock torque spec?
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Old June 24th, 2020, 07:33
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Re: 5/8 Ubolt torque

No. Torque is a measurement of how much you are stretching the bolt, and it has to be stretched to a certain amount to properly do its job or to stay tight (separate and equally important issues!).

If you aren't going to torque the bolt to its own proper spec, you are making a DANGEROUS mistake and need to go to a smaller bolt that you will torque to spec.


But if you crush an axle tube with 200 ft pounds, it was dead anyways. Figure your jeep weighs 4000 pounds and sits on top of it...
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