2022 303 RLS Lug But Torque

**Butcher** · 06-13-2022, 09:49 AM

Yes, lubing the threads will effect the true clamping pressures.

I was totally surprised by the Firestone incident. One bolt broke off/missing [Mercedes and many German manufacturers use bolts] the other 4 were tight but not clamping the wheel. I was afraid that two of the 4 bolts would break if I removed them. I was able to get two of them off. I lubed the threads and secured the wheel enough to drive it to the clients home. They were not cross threaded.

It was clear to me, the bolts were tight but not holding the wheel on. Why clear to me and not the last tech? I do not know but as soon as we take repairs like this seriously, things like this will keep happening.

**Hoopy Frood** · 06-13-2022, 09:55 AM

Originally Posted by Butcher

Yes, lubing the threads will effect the true clamping pressures.
...

Uh, I don't agree with that statement, lubing the threads will necessitate changing the torque values to reflect that. But clamping force will remain the same as the lubricant has no direct effect on clamping pressure, just on the torque settings necessary to attain the proper clamping force.

**Butcher** · 06-13-2022, 10:08 AM

The Mercedes I worked on had the proper torque on the bolts and there was no clamping pressure on the wheel. Yeah, that is the worst case scenario but torque is not measuring the clamping pressure, just the ability of the bolt/nut to turn. If there is so much friction [or reduced because of lube] the clamping pressure is directly changed.

The new fangled way of tightening fasteners is the torquing the bolt with a low value the, turning the bolt a certain amount of degrees. That way, it does not matter what the torque is. All the bolts/nuts are seated, then turned the same exact degree. They all will have the same clamping pressure but all would have a different torque value.

Most specs are with clean/dry threads. I like to use penetrating spray if I feel the bolts are hard to turn. That stuff does not change the clamping pressure much.

https://crane-electronics.com/genera...ue-tightening/
https://www.engineeringtoolbox.com/t...ts-d_1693.html

**Hoopy Frood** · 06-13-2022, 10:28 AM

Originally Posted by Butcher

The Mercedes I worked on had the proper torque on the bolts and there was no clamping pressure on the wheel. Yeah, that is the worst case scenario but torque is not measuring the clamping pressure, just the ability of the bolt/nut to turn. If there is so much friction [or reduced because of lube] the clamping pressure is directly changed.

The new fangled way of tightening fasteners is the torquing the bolt with a low value the, turning the bolt a certain amount of degrees. That way, it does not matter what the torque is. All the bolts/nuts are seated, then turned the same exact degree. They all will have the same clamping pressure but all would have a different torque value.

Most specs are with clean/dry threads. I like to use penetrating spray if I feel the bolts are hard to turn. That stuff does not change the clamping pressure much.

https://crane-electronics.com/genera...ue-tightening/
https://www.engineeringtoolbox.com/t...ts-d_1693.html

Wow, we may have to just agree to disagree.

As I said, lubing the threads will not affect clamping pressure, and torque readings should be reduced if you use any kind of lubricant.

Actually that is not a "new-fangled" way of setting the tightness/clamping force of a bolt. "Torque to yield" bolts have been in use for many years, but mostly in commercial/aviation applications. They have become more common with the proliferation of aluminum blocks and heads in the automotive industry. Volkswagen used them in their diesel engines back in the 80's.

**Scott'n'Wendy** · 06-13-2022, 10:58 AM

To the OP, the lug nut torque value is listed on a sticker on your tailer's pin box. (unless someone removed it) On my 303 it said 110 ft/lbs and indicated the pattern to use tightening.

**Canyonlight** · 06-13-2022, 12:15 PM

Originally Posted by Scott'n'Wendy

To the OP, the lug nut torque value is listed on a sticker on your tailer's pin box. (unless someone removed it) On my 303 it said 110 ft/lbs and indicated the pattern to use tightening.

Funny you mention this. I thought about posting the same information on a sticker on our pin box but my picture taken in 2014 just a year after our 303 was built had faded in 11 months thus the writing was not legible. And back then, GDRV wrote the torque applied at build......not the actual Lippert axle lug torque specs. We just got the Lippert specs using our axle build sticker serial number along with the information from Lippert for our then, 5.2K axles.

Dan

**Butcher** · 06-13-2022, 12:24 PM

@Hoppy Frood I think I get what you are saying and I would agree. If you need 100 pounds of clamping pressure, you may need 50ft/lbs of torque to achieve that on a dry bolt and 40ft/lbs with a lubed bolt. If that is what you are saying, you are completely right.

What I was trying to say is that using the same torque, a lubed bolt would apply more pressure than a dry one.

If you do not agree with that, then I agree, we'll just have to disagree and there is nothing wrong with that.

**Hoopy Frood** · 06-13-2022, 01:21 PM

That's correct: a lubed bolt should be torqued to a lower number than a dry bolt. Done correctly a dry bolt, and a lubed bolt will apply the same clamping force.

**MAiman** · 06-15-2022, 08:15 PM

Our 2022 Reflection 303 RLS came with a sticker on the pin box that said to torque the lug nuts to 100 ft. Lbs. That is the setting that works for me. Just be sure to use a 6 point socket or you can damage the outer covering. I also use a deep well socket.