LCA shock mount torque value ?
08-06-2017, 10:45 AM
#46
Rennlist Member
My guess is that the "replacement" studs, shipped with the bracket from Porsche, are not as good as the original material.
We need to keep in mind that the Porsche Factory isn't using these pieces to assemble cars....I doubt they even test replacement parts. If this stuff was happening on the assembly line, it would be solved very quickly....
The front bolts for the lower control arm are speced to 62 ft lbs or whatever and I am embarassed to say I know they cannot take 88ft lbs. On one occasion quite a few years ago I was tightening the things and I made the cardinal error of assuming I knew the correct torque value based on bolt size. At about 75 ft lbs I could feel the bolt stretching but the torque was not going up. Fortunately I had the presence of mind to realise something was wrong, went back to the WSM, checked the torque values and nearly did myself. Now, every time I do a job, I make a list of the fasteners and the specified torque even if I know full well what it should be.
Regarding the OP's original failure- it seems as though he has been singularly unlucky to experience two different failure mechanisms on the same piece of kit. Whereas plating these brackets and the like is a nice feature, plating high tensile bolts to my mind is not something that should be entertained. Whether this caused the original failure I do not know but to date I have not seen any other explanation that seems more credible. I have had my bolts undone more than most because of the nuber of times I have been to the alignment shop. I am guilty of not replacing the nuts and have lived to tell the tale so far but all this makes me wonder whether I am living on borrowed time/luck and I must say I am not comfortable with that given those fasteners are probably one of the most safety critical items on the car. For sure I intend to replace those nuts in the very near future and possibly drop the torque a bit.
