Kwik-fit and a puncture.

Or try interleaving the pages of two books. They push in fairly easy, but you try parting them again by pulling.

Yes, but in the tightening process you are fighting against the two surfaces you are pulling together. In undoing the force (no jokes about the film please) is working with you.

No, *you* didn't, but the OP said "nowhere near that tight".

Not any I've seen in the last twenty years or so.

Hang on! I'm having a "Life on Mars" moment!

Re-torquing head bolts went out with OHV engines, if not before.

Chris

Most engines still have overhead valves:-) But not many need re-torquing nowadays.

:-)

Chris

angle tightening is rather different to torque tightening.

Bingo!

:-)

who undoes a bolt straight away?

It's much more accurate being the main difference.

I must be the only person that had to fit, e.g. a wheel, only to remove it a couple of days later :-) I must have been too impoverished in my younger days, get the car running, get the parts, then repair.

Talking about wheels, once they have been on the car for a while the threads seize a bit on the hub (assuming the car has bolts), and also the bolt itself can seize nicely on the fase of alloy wheels. That means. a lot of force is needed to undo the bolts (or air impact tools which you .probably use most of the time ... good on you). Surely you must have had wheels stuck on hubs (esp. alloy wheels) why not the bolts or nuts being stuck the same way :-)

However, I agree with you, even if I don't grasp the essence of it, it feels as if less force is needed for torquing than for undoing a bolt, even it has just been tightened. Going back to the OP's comment, the bolts might have been loose or there was no "crunch" when they were undone because they had not been on long enough.

Charles

I am often frustrated when attempting to undo wheel nuts, the air impact wrench I have is rated at 600 lb ft in reverse, yet sometimes cannot undo a wheel nut put on by some monkey at a tyre shop. It is often necessary to get out the big bar and 4ft scaffold pole, which I do not believe was used to do them up!! Therefore there is more power needed to undo than to do up.

Presumably slacken it and re-tighten, or am I missing something?

Yes, but the point was that (poorly designed) components can give after a relatively short period of time - without external influences.

that is the right way, many people just try to apply the original torque without the slacken first bit.

I've had countless heads off in my time - and used to religiously check the torque setting after a few hundred miles. And never once found it needed it. I reckon they recommend that to catch ones which weren't properly torqued in the first place.

It's a brand new car that hasn't had its first service. It's only 3 weeks old.

When do they get the car back after delivery to check the wheel bolt torque? There's not a 500 miles or whatever check anymore - and hasn't been for ages.

Err, what are you talking about? Bolt torque or the puncture repair?

If you're referring to me it wasn't my car.

How about all the other fixings in a car that get hot too? Should they all be checked? If not what makes the wheel ones special? Especially since in general they are vastly over engineered?

Right. That ruler was what the KF guy used first - then added a red circular thingie. Which had no markings.

Maybe so - but do they check every single fixing on the car? The wheels and tyres were an extra, though. Is that sort of thing dealer fitted? The car wasn't stock - took 6 weeks to arrive.