I never understood the concept of "torqueing" bolts.

[Keyan]

What exactly is it? What bolts need it done? What happens if it's not torque'd correctly? So confused...

[SWortham]

Usually it's a matter of what the bolt is fastening. If you overtorque, you could bend metal which is meant to form a seal, you could strip the threads, sometimes you could even break the bolt.

And of course some bolts are more critical than others.... for example I don't put much time & effort into torqueing the nut for the wire on my battery terminal, but I would with my wheels.

[sed]

Torquing a bolt:

is the amount of force used to "tighten" the bolt or nut. Most cars use 75 - 100 lbs of torque on the wheel lugs. That means, you have to exert 100lbs of force to tighten the bolt to spec.

thats all

shawn :)

[YBKewl]

In fact, torque is lbs/ft. So to torque your wheel to 100 lbs/ft, you need to apply 100lbs on a 1 foot wrench or 50lbs on a 2 feet wrench.

[Elkane7533]

sorry guys but it's lb-ft. they also use ft-lb.

lb/ft would mean pounds per feet. torque is force multiplied by length, not divided by.

Anyway, they have torque spec's for each bolt because that way the bolt is not too loose or too tight, causing sheer. if the bolt is too tight, it might sheer or strip and you don't want that.

[Keyan]

I was re-installing my dash the other day, and I was screwing in a "4" bolt. I kept on tightening and tightening...and then the head of the bolt snapped off. lol.
Too much torque? ;)

[SuperGLS]

Elantra2.001 told me the numbers on the head of the bolt simply identifies the "hardness of the bolt." So, a 4 is pretty weak I guess, and that's probably why you broke it. First just hand tighten them, then give them a couple good turns with a wrench and you should be set.

[Jtown]

One example I can think of the proper reason for torqueing, is an intake manifold. Mos intake manifolds have 6 to 10 bolts that fasten it to a motor. The intake manifold must have a good seal and the means that the plane of the intake has to be completely flat. If one bolt is tighten more than another the mating surface of the intake will bend causing gaps and leaks.

[sed]

or wheel lugs!

shawn :)

[04 elantra cvvt]

Or any critical part. On the dash, use common sense. If you are going into plastic, it probably doesn't need to be super tight. If you are boing into metal, it can probably be a little tighter. Just remember, use common sense when you are working with interior parts.