Jeep Wrangler Forum banner

Engineers out there

1K views 9 replies 5 participants last post by  cypher89 
#1 · (Edited)
I'm using 9/16 grade 8 shoulders bolts (poly kit) for my control arms and track bars.

Problem is I torque em to the 125 ft lbs spec and I can still turn the nut/bolt as a whole pretty easily.

Is the bolt no good after one torque ... or three or five times ?

Should I be replacing the bolt/lock nut or both. Maybe a lock washer ?

Thanks
 
#2 ·
When you say you can turn them easily do you mean by hand or with a wrench (leverage)? Is the bolt fully threaded or not? If it isn't, you may be hitting the unthreaded portion of the bolt which will give you the "torque" but the nut will not be flush (it may make contact against a surface, but it may still be bottoming out on the threads).

Have you checked the calibration on your torque wrench? When I was an aircraft mechanic, we had a bench check for calibration, and an annual laboratory recalibration for our torque wrenches. I have a couple that I picked up from Harbor Freight (meaning cheap), and they suck. I wouldn't use them for any critical application. I use the three footer as a breaker bar now.

As far as reusing bolts multiple times, that shouldn't be an issue in "normal" applications. Any critical hardware we used could be inspected (NDI, Dye penetrant, eddy current (sp?), etc.), but the rule of thumb was; never reuse self locking nuts, but bolts were fine for reuse.

HTH
 
#3 ·
BakedInMN said:
When you say you can turn them easily do you mean by hand or with a wrench (leverage)? Is the bolt fully threaded or not? If it isn't, you may be hitting the unthreaded portion of the bolt which will give you the "torque" but the nut will not be flush (it may make contact against a surface, but it may still be bottoming out on the threads).

Have you checked the calibration on your torque wrench? When I was an aircraft mechanic, we had a bench check for calibration, and an annual laboratory recalibration for our torque wrenches. I have a couple that I picked up from Harbor Freight (meaning cheap), and they suck. I wouldn't use them for any critical application. I use the three footer as a breaker bar now.

As far as reusing bolts multiple times, that shouldn't be an issue in "normal" applications. Any critical hardware we used could be inspected (NDI, Dye penetrant, eddy current (sp?), etc.), but the rule of thumb was; never reuse self locking nuts, but bolts were fine for reuse.

HTH
With leverage yes. This kit was put together for the control arms and TB's

And :hide: yes I do own a HF wrench BUT. I can lean into pretty good and still have the same results.

My lca axle joints are fine.
 
#5 ·
harleydragon said:
sounds like your threads are bottoming out..add a washer or 2..or go to a shorter bolt
It does seam that way but I doubt it's the case. This hardware kit is for the Jk.

Actually I know it's not the case with the TB bolts because the shouldered part just clears the bushing. Then threads the rest of the way, and through the mount.
 
#6 ·
What did the manufacturer say about this when you called them?

Take care,
 
#8 ·
make sure you are torquing the nut side otherwise your wrench won't be reading true fastener torque only applied torque. Using good hardware 125 is not too much for a 9/16" bolt such that you would exceed its yield strength and cause the bolt to permanently lengthen. All steel stretches softer steel stretches more, harder steel less but becomes more brittle.
 
#9 ·
cypher89 said:
make sure you are torquing the nut side otherwise your wrench won't be reading true fastener torque only applied torque. Using good hardware 125 is not too much for a 9/16" bolt such that you would exceed its yield strength and cause the bolt to permanently lengthen. All steel stretches softer steel stretches more, harder steel less but becomes more brittle.
Thanks ... Yes I try to tighten the nut side if I can. The axle side TB can't be tightened this way. the bolt only goes one way and the nut is buried. Same with some of the other bolts where the nut is buried in the frame.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top