Re: Torque Wrench help needed Hi,
Just some thoughts of a newbie to the Indian car scene.
I have no experience (yet) here in Delhi, but I've lived in several European countries and the last three years in Kansas City USA. Do most of maintenance and repair on all my cars myself
Any (western) professional garage will always use a pneumatic wrench to get the wheel bolts tightened quickly, but will also alway use a proper manual torque wrench to properly torgue the bolts individually. Unless you invest in very fancy pheumatic or electrical wrenches where you set the correct torque, this is the only way to do it.
You need to figure out, either the setting or the time you use your pneumatic gun that gets you tongued to about 60-70% of the recommended value. From there on use a manual precision torque wrench. It will only turn a little bit from there on.
On the matter of using oil/lubrication etc. If the manufacturer manual doesn't mention it specifically don't use anything! In nearly all cases bolts and rim should be dry, free of dirt and grime. Again, unless specified otherwise.
Bolt/nuts should be able to turn freely by hand, or at least with very little resistance initially. If not, clean/fix the thread first.
On the matter on checking the correct torque after 50-100 kilometer. Recommended as a common practice for most western countries, although admittedly very few actually get around to it. In the US if you go to a "quick fitter" to get some new tires, you will need to sign a form which stipulates you need to do so. Because if they don't point it out to you and something happens you could sue them! Welcome to the good old USA!
What you actually do; just take the manual torque and redo all bolts. You don't loosen them, you just put the wrench on it and torgue it again to the prescribed vallue. The idea here is that there might have been some dirt and or slack when you initially bolted the wheels back on. After a little driving that might settle and you need to retighten the bolts to their prescribed torque settings.
I've always done so, but I dont think I've ever seen a bolt or nut move on the re-torqueing. But still, better save than sorry.
Once, I had my Alfa Romeo Spider wheels re-alligned and at my request they also swapped the wheels back to front. Easy to do, once on the ramp. When I got home, two of the wheel bolts where half out. They used the air gun, but forgot to torque one set of wheels! So they were professional enough to always manually torque, but made an honest mistake. Still, could have been a bit of a problem if the whole wheel came off.
How important is torqueing properly? Well, many different opinions, on this forum as well it seems. Over torqueing can lead to damage to the bolt/thread and worst case the rim. So from that point of view it makes a lot of sense. Too loose and you might loose a wheel. See my experience, although that was a case where the bolts were never set properly to start with
Being a former Marine Engineer and having worked on very large diesel engines I adhere rigorously to proper torqueing of any bolt/nut on any engine for that matter.
For instance proper torque setting and procedure on a cylinder head will be the difference between no problems and more or less immediate problems. My personal belief; lot of people don't think torqueing of wheel nuts is of any real value. Fact is that most wheel nuts get overtightened. From a safety point of view that's no problem. (in most cases)
It does become a problem when you have a flat, in the middle of the night, rain pouring down, in the middle of nowhere and you find out that your car toolset consist of a pathetic little wrench that starts bending the minute you point it at the wheel bolt. Then you wish you'd used a proper torgue wrench because you might have stood a chance undoing the bolts!
By the way, I carry a proper set of tools in each one of my cars all the time.
So you could debate the value of torgueing the wheel bolts perhaps. I'd say, from an engineering/professional point of view, you should always do it.
Jeroen |