Bone breaking shock waves when tightening / tightening wheel nuts - copper grease on RAD seats?

[Stocho]

Hi,

When tightening/untightening wheel nuts on W211 I am getting extreme shock waves. So the resistance does not increase uniformly as the bolts are tightened but there are lapses in resistance causing shock waves. Similarly when tightening.

I applied copper grease to bolt threads but it did not help. I now believe that these shock waves are due to friction between RAD bolts and rad seats of the alloy wheels.

It might be that I am over-torquing but on the other hand if the perceived torque is provided not through thread tensions/friction but through rad seat friction I fear that stopping as soon as the 110Nm is reached could lead to not properly tightened bolts.

I am thinking of applying copper grease to the RAD surfaces as well. I think it will result in the torque increasing continuously as bolts are tightened with no sudden lapses in torque as bolts are tightened that cause shock waves. This will also allow me to stop at 110Nm or so in confidence that torque is not about to collapse if I tighten just a bit more.

What are the views on this?

 

[whitenemesis]

Hang on, I'll get the popcorn

Copper grease on roadwheel bolts ? | Technical matters | Back Room Forum | Honest John

 

[zenman63]

Just try one and see if it is the tapper grabbing.

 

[Stocho]

Hang on, I'll get the popcorn

Copper grease on roadwheel bolts ? | Technical matters | Back Room Forum | Honest John

Thanks a lot for the repply.

I already applied to the thread - did not help. So the question now is not about the thread but about RAD surfaces.

 

[whitenemesis]

Have you tried cleaning up the treads? Not just lubricating but wire brushing, or using a tap and die?

 

[bob6600]

It does sound like the thread and/or bolt need cleaning. Also check they haven't been cross threaded.

 

[KennyN]

The problem with some wheel bolts is that generally there are a few threads that protrude the rear of the hub meaning they get corroded and can cause problems when removing them as you are driving the corrosion through the clean threads of the hub.

Remove them and either run a die nut over the threads of the bolt or use a thread file to clean them up.

It maybe cheaper to buy new bolts as metric fine die nuts will not be cheap.

Kenny

 

[Stocho]

Hi, Thanks a lot for the repplies. It seem the opinion is that theproblem is with the thread, and yes there as a bit of rust at he very end - probably just the very last "circle" of the thread. However I did apply copper grease to the thread which should have made things a lot better - provided it is the thread that is the problem.

I do see some friction marks on the RAD surfaced of the bolts though - so inclined to think it is the friction between the RAD seat of the wheel and the RAD surface of the bolts.... I am now starting fearing that perhaps the radius of the (RAD surface of the) bolts is wrong, though that would be seem unlikely.

 

[Doodle]

All of these problems will disappear with the patented Kwik-Fit "2 ugga-dugga" impact driver method

 

[190]

I lube both the threads and the RAD surface then tighten to a 15 % reduced torque level. NO question that the correct method is no lube which would be fine if things didn't rust as well as being grossly overtightened by some members of the "trade" Talking of overtightening I wonder if it's possible the bolts have been permanently stretched in the past in which case they are scrap.

 

[slade1]

I lube both the threads and the RAD surface then tighten to a 15 % reduced torque level. NO question that the correct method is no lube which would be fine if things didn't rust as well as being grossly overtightened by some members of the "trade" Talking of overtightening I wonder if it's possible the bolts have been permanently stretched in the past in which case they are scrap.

Members of the “trade”. I had 4 wheels refurbished and new tyres fitted, it was impossible to take the wheels off to clean, went back to refurber, they did a good refurb job, got them to loosen the nuts. Now OK. Have used copper slip for decades.

 

[Rich H]

Talking of overtightening I wonder if it's possible the bolts have been permanently stretched in the past in which case they are scrap.

+1