So as I actually get ready to use the handy chart I made I have a question. When checking bolts, do you have to loosen them all and retorque or just check torque and loosen and retighten IF you find it to be loose. Seems like a lot of opinions on the web. Not to beat a dead horse I just want to do it right.
I will give two examples, using car or truck wheel lugs. #1 you had your wife take her car in and had the snow tires swapped for the summer mounted tires and rims. You asked if they used a torques wrench and the answer from anyone would be I don't know unless it was a small garage and you could watch them. In this case, my experience is they use a impact wrench and torque is usually over the recommended, in a case like this I back off then re-torque myself, the reason being is the torque on the wheel is shared by all the wheel lugs, one that is torqued to a greater value than the others could either stretch or cause that stud to fail under severe braking or a skid.
#2 You installed the summer rims which are alloy and followed proper torque procedures ,a week after it is possible the hub-centric rims have seated slightly due to corrosion or oxide, in this case, go over all the wheel lugs with the proper final torque setting, no backing off required as any changes while mounted will not cause a over torque condition.
Anytime you are dealing with multiple bolts fasting a common device, such as a head of a cylinder, it is important to follow torque procedures and as a example when doing the valve shim, you are torquing inch pounds, you go cross pattern and work up to maximum torque in stages
.Not full torque right from start.
When talking fasteners like the front brake calipers, bolts that share mounting either single or 2 bolts, I use blue loctite sparingly, I also use to a certain degree a lube torque chart which is lower torque. When doing these same bolts with no loctite, torque them once at proper torque, if after 10,000 KM it says to check, use your original setting. If you find them loose, pay attention, this may call for loctite.
Some fasteners like Volkswagen says to reach proper torque then 1/4 turn clockwise. Many of those bolts are one time use.
I hope that helps.