I've been working on my Benz, following the shop manual instructions. It seems that every bolt and nut is the self-locking variety, and available mainly through the dealer at exorbitant prices. To be honest, I had never heard of such beasts, so I did a little research. Actually, they do exist, and the science behind them is quite sound. Those Benz engineers do know what they are doing. Here is a very useful link, and video clip:
Vibration Loosening of Bolts and Threaded Fasteners
The article states that "...the chemical locking category provides the greatest resistance to vibration loosening...". Perhaps, hardware nuts and bolts with Loctite will do the trick?
Does anyone have any information on this?
loctite, when used properly can provide a very good locking against vibration, BUT, proper application with the proper selection of loctite is the key. However, there are many things that can go wrong and weaken the bond. The joint must be absolutely clean of dirt or oil, the proper prep agent is highly recomended, and the locktite needs to be fresh, not old stuff sitting around. You also need to know what materials and platings are on the part to select the proper adhesive, they are not compatible with all platings or all materials if you want the rated strength.
You also need to make sure you use the proper locktite for the application, e.g. low strength, regular strength, or the high strength heat removal type specific for the bolt size (diameter). The max temp rating needs to be taken into account and if the assembly will be exposed to oil or other fluids, which affects which locktite product to use. So, it isn't as easy as "grab a tube of loctite and I'm done." In fact, unless you are replacing a lot of fasteners, you could easily spend more on the proper adhesives, prep agents, cleaning agents and bonding agents than you will on hardware.
Instead of paying dealer prices for hardware, any good old fashioned hardware store will have self locking hardware, either of the "nylock" variety or self locking flange or regular nuts that have been deformed of the proper grade rating.
One other thing to remember, if the original application used self locking hardware, the torque spec's took that into account. Switching to locktite will change the required torque downward since you don't have the torque of the interference to overcome.
Again, each has it's advantages/disadvantages, personally I don't interchange locktite and mechanical previailing torque fastener for any application that is safety related or internal to an assembly