Rear Axle Nut TSB - DIY
11-27-2017, 06:29 PM
#353
Registered User
Torquing Process
Your article is a benefit to all. One thing I am concerned about it the use of cheater bar to assist in torquing. Please understand, a proper torque is the use of the device as is; to extend the length of the torque handle is a major concern. When torquing 180 ft lbs. using a standard configuration is accurate. however, when you extend the length of the handle, your torque will be lower because leverage of use. Only when you keep the length of handle the same distance will the measurement remain the same. To torque using a cheater using the same torque value will damage your threads due to over torque. Your chances of stretching the threads are significantly increased.
Just my input. you can Google on proper torque and the use of cheater bars.
Just my input. you can Google on proper torque and the use of cheater bars.
11-27-2017, 06:40 PM
#354
Your article is a benefit to all. One thing I am concerned about it the use of cheater bar to assist in torquing. Please understand, a proper torque is the use of the device as is; to extend the length of the torque handle is a major concern. When torquing 180 ft lbs. using a standard configuration is accurate. however, when you extend the length of the handle, your torque will be lower because leverage of use. Only when you keep the length of handle the same distance will the measurement remain the same. To torque using a cheater using the same torque value will damage your threads due to over torque. Your chances of stretching the threads are significantly increased.
Just my input. you can Google on proper torque and the use of cheater bars.
Just my input. you can Google on proper torque and the use of cheater bars.
A bar increases torque.
The point is to torque it to 180LB-FT first. With a standard torque wrench. I'm assuming with dry threads?
Then, using a bar to help you turn the nut, turn an additonal amount of degrees.
I don't use a bar. I torque to 180LB...and then I use an impact to turn the nut the rest of the way.
11-27-2017, 06:42 PM
#355
Nothing sounds wrong. Driveline parts are movable. If you move them, they will clunk against each other.
11-27-2017, 07:00 PM
#356
What size is this thread anyway? M24? M27? 1.5mm pitch?
Max dry torque for M27 is ~1100-1200LB-FT (For Class 10.9). 780ish LB for a M24. But dry torque is MASSIVELY inaccurate for its tension relationship.
But...anyway....no...hell no, you won't snap or strip the thread with your puny ~360LB-FT. Even Class 4 hardware will take over 300LB-FT in M27.
If its easier, maybe using 250-280LB-FT with lubricated threads is a better way to get enough tension to make the bearing not click.
Max dry torque for M27 is ~1100-1200LB-FT (For Class 10.9). 780ish LB for a M24. But dry torque is MASSIVELY inaccurate for its tension relationship.
But...anyway....no...hell no, you won't snap or strip the thread with your puny ~360LB-FT. Even Class 4 hardware will take over 300LB-FT in M27.
If its easier, maybe using 250-280LB-FT with lubricated threads is a better way to get enough tension to make the bearing not click.
11-28-2017, 05:11 AM
#357
You don't need and I doubt you can find a torque wrench capable of this torque. The TSB requires tightening the nut 60° tighter than it was. That's one flat of the 6-sided nut. Remove, clean, regrease, and return the nut to where it was originally staked. Then turn an additional flat and restake. Standing on the end a 24" breaker bar worked for me. 180 pounds on a 2 foot handle is 360 pound-feet. 
BTW we used this same Harbor Freight 3/4" drive bar to remove the crank pulley from a car during a turbocharger install. Got the pulley off but splayed the handle fork. Was nice to have a welder.
Anyone in the Richmond VA area who wants to do this TSB let me know, the wrench is just sitting here feeling unloved.
-- Chuck
BTW we used this same Harbor Freight 3/4" drive bar to remove the crank pulley from a car during a turbocharger install. Got the pulley off but splayed the handle fork. Was nice to have a welder.
Anyone in the Richmond VA area who wants to do this TSB let me know, the wrench is just sitting here feeling unloved.
-- Chuck
11-28-2017, 08:31 AM
#358
Torque is only a relative measurement. The ultimate goal for fastening is almost always the tension or clamping load created from a torque value.
Your applied force at the handle turns into torque at the center of the socket. That torque works to turn the nut, which uses the threads as a ramp. The nut "climbs" the threads to clamp the hub to the axle.
Yes? Yes.
Since a lot of your applied force goes into friction on a dry fastener, less tension per torque is achieved. You're wasting your torque/force on friction. The nut won't "climb" those threads as willingly as you'd like.
Dry torque also results in huge variances in clamp output. This is why we're using degree turns rather than torque for the final result. Degree turns is degree turns. It might take 300, 400 or 900, or whatever number of LB-FT to get those degree turns...but your goal is the degree turns. Regardless of torque.
However, you're still using 180LB-FT as your starting point. So there is some reference to torque.
My proposition is to use lubricant on the threads and nut face. Then...use a torque wrench like civilized man. I am willing to bet that ~250LB of torque with a lubricated fastener will get you the same amount of degree turns and the same clamp load as jumping on a 3/4" bar does.
Yeah yeah. I already know nobody is reading this.
Your applied force at the handle turns into torque at the center of the socket. That torque works to turn the nut, which uses the threads as a ramp. The nut "climbs" the threads to clamp the hub to the axle.
Yes? Yes.
Since a lot of your applied force goes into friction on a dry fastener, less tension per torque is achieved. You're wasting your torque/force on friction. The nut won't "climb" those threads as willingly as you'd like.
Dry torque also results in huge variances in clamp output. This is why we're using degree turns rather than torque for the final result. Degree turns is degree turns. It might take 300, 400 or 900, or whatever number of LB-FT to get those degree turns...but your goal is the degree turns. Regardless of torque.
However, you're still using 180LB-FT as your starting point. So there is some reference to torque.
My proposition is to use lubricant on the threads and nut face. Then...use a torque wrench like civilized man. I am willing to bet that ~250LB of torque with a lubricated fastener will get you the same amount of degree turns and the same clamp load as jumping on a 3/4" bar does.
Yeah yeah. I already know nobody is reading this.
The following users liked this post:
Slowcrash_101 (11-28-2017)
11-29-2017, 06:23 AM
#359
Community Organizer
I did and your point is quite valid. I know you are looking to essentially clamp something down but you have to exert force on it do do so. You are spinning a nut which is just like climbing a hill. Or sliding something UP that hill. Let's take a sled on a hill and it's summer and you are on pavement. Tough to pull up there isn't it? Let's make that surface have less friction and put snow and ice on the road. Let's say you have ice boots on to walk.......much easier now isn't it to do the same job! Same with your oiled bolt but on a much smaller scale.
