Ubolts under torqued

hmmm... I just did a little reading. (something I should have done more of before grabbing the torque wrench)

Apparently, the Ubolts are supposed to be tightened in a criss cross fashion.

On the drivers side, I think I did the inboard ones first, then the outboards ones. On the passenger side, I think I went in a more clockwise around the square pattern...

How important is the criss cross thing? Hope I didn't just screw things up...

 

You know another thing to think about is that U-bolts are a "torque to stretch" bolt. A predetermined setting isn't always going to be the right torque if you are using non-stock U-bolts and if you have removed them and re-installed technically you should replace the bolt.

 

I have no Clue
Maybe someone else will have the answer for ya.
My guess would be..............
If the U-Bolts were long enough to accommodate one more leaf, they'd have reused them.
Unless the new Leaf Pack came with new U-Bolts
Unfortunately my "before" pictures don't show that detail.
I think I had 1/2" - 3/4" of excess thread showin' when I checked the torque.
Disclaimer: All of the above is just speculation

BTW: What prompted the question?
I'm (pretty) sure the Dealership wouldn't reuse bolts that were to short.


CC

 

I think it's ironic that this thread popped-up tonight. I just got my 3" lowering block kit from StreeTacos.com (yes, lowering blocks... not a type-o ) and when I went to remove the stock U-bolts on my 2 month old 2013 regular cab, I was expecting the worst. However, I couldn't believe how easy the bolts came off, even with just a 12" long socket wrench. I guess I'm happy I didn't need to use brute-force to get the bolts off, but I'm pretty darn sure my new bolts are going to go on tighter than that (especially because of the 3" blocks).

 

I have mine torqued up to 75 now, no problems. Just went on a VERY rocky road up close to the Continental Divide (right by where my avatar pic was taken, actually), a 4LO road, she's fine.

 

When they did the TSB on my truck It was with all new hardware..
They used 19 mm bolts and nuts.

 

Hmmm. Ok. I think I'm fine then. As I mentioned before the thread counts are very close, off by maybe a thread at most. (I may mic' it tomorrow just out of curiousity)

The drivers side are the ones I was more concerned with, as I brought the two inboard nuts up to new spec before the outboard ones. But I should make it clear that I did not back any of the nuts off from factory tight at all; I just added more turns until my wrench clicked. So while I didn't tension each Ubolt evenly on each leg, there was at least the factory torque on the outboard leg nut at all times holding that side of the Ubolt firmly against the pack while I brought the inboard nut up to 75 ft-lb.

I'll do as suggested and drive it a bit more as there's only 600 miles on it thusfar. When I hit 1k and do the first oil change, I'll check the torque again.

Thanks again for all the help guys.

 

That's a good idea. What website can I find that at?

 

Once again thanks to everyone's reply and all the info. Great stuff !!!

 

Now I understand the question. Think consensus is, 37 ft/lb is a typo.
I looked at a .pdf version I have of the TSB. (attached below)
Unfortunately the links to reassembly & Installation go nowhere.
Has a list of links by truck year, then goes right to, how to align it.
But I did notice in the "Parts Information" listed the 4 U-Bolts.
Excellent Question btw, This is how we make progress.


CC

 

Yeah I looked it up too. Not very helpful for what we are looking for. But I did see as well that they do come with new u bolts. Maybe the non tsb u bolts are designed at 37ft lbs and the tsb u bolts are redesigned to 75 or 80? I don't know , just saying.

 

I don't think there is any grade of steel used for u-bolts that would yield at 37# in that size. If it was that soft, you could bend it by hand, and that wouldn't be good for u-bolts. There are standard grades and sizes, and recommended torque for what is typically used is around 80#.

It's your axle. It pushes your truck around using the u-bolts as its grip on the rest of the truck. Make sure it has a good grip. 37# just isn't right.

 

I'll just leave this here

 

Ok, read it you can have it back now.....

C'mon guys use your common sense, if up to 2004 (end of 1st gens.)
The factory torque was 90ft.lbs. & in 2005 (1st year of 2nd gens.)factory torque drops 53ft.lbs to 37ft.lbs does this seem reasonable ? does this make any sense ? Sure doesn't to me & keep in mind I can take my stock Ubolts & nuts right now throw them on a 2nd gen axle & fit perfectly because they're the same..

 

Just went under my (Canadian) 2013 DCLB TRD Sport. I'm pretty sure the ubolts were at 37ftlb's. I could easily remove them with a standard socket rench.

I torqued mine to 70ft lb's just to be on the safe side. Didn't feel comfortable going to the full 80-90 just because that's a whole lot more than 37! (just in case we are all wrong!)

Cheers,

Jay

 

^^^ did this exactly today at 70 but now im thinkin a lil' tighter..80 should good, i lost alot of noise after i torqued em

 

I'd be comfortable with 70ft.lbs. glad you guys checked...

 

Finally torqued mine to 70# today.

 

Hey guys just an up date. The other day I stated that after checking the u bolts they were loose . At that time I torque them to 40 ft lbs. After driving the truck just a couple of times I checked them again and low and behold they were loose again. So I decided to torque them to 65 ft lbs. just like the chart said. I did mic up the stock u bolts and they measured 1/2in. So I will drive it a couple of days and recheck them. At this point I am starting to lean torque 37# being a typo !