Thanks for all the replies!

PapaTravis: What you said makes perfect sense. Changed my oil and trans fluid last night, Mobil 1 all the way. Man, what a difference! But that's a story for another thread... Anyway, the torque spec for the drain plugs are 14-21 ft./lbs. I initially torqued to 17 lbs. Oil plug leaked, trans plug was fine. Re-torqued oil plug to 20 lbs, no more leak.

 

hmm, sounds familiar.

 

A bolt that has some form of lubricant on the threads, anti seize, or loctite will torque differently than a bolt with dry threads. I always go 75% of the range. Do you know anybody who has a torque wrench for the master cylinder cover? 6-7 in-lbs. Do they even make such a thing?

 

Snap-on has a screw driver type torque wrench that goes that low. At least they used to.

 

Threaded fasteners are tension devices. They actually stretch like springs. Based on the fastener size and material the required torque values will differ. The torque values in the book are, I'm pretty sure, usually for a dry fastener. Some of the applied torque goes toward overcoming friction in the threads when tightened dry. If you use some form of lubricant on the threads, definitely shoot for the lower end of the range or you may, by applying more of the torque to stretching the fastener, over-stretch it.

As was basically said a few posts up, the range of values encompasses the minimum and maximum stretch of the fastener to achieve the desired results. Too little stretch and it won't hold, too much and it'll fail.

 

I'm old school .. no torque ... blue loctite and it's good to go... If anyone on I-5 finds a bigaxel nut ... it's mine. [sm=biker2.gif]