gnosis@fluke.UUCP (Chris Villani) (10/02/85)
In a recent article about replacing Honda rotors and bearings a gentleman mentioned that he torqued down his wheel bolts. It isn't clear in his article how he performed the torquing procedure, it may have been fine, but I was reminded of a sad story the I recount here as an expression of caution to us all: A couple of years ago a young women had some ordinary brake work done on a 76 BMW 2002 at a shop in Bellevue, WA (this is near Seattle). This shop specialized in such vehicles. A newly hired 'mechanic' remounted the wheels (alloy rims by the way). Some where he got the notion that the wheel bolts needed to be "torqued down". He did so with all the force the shops impact wrench could muster. A job well done he thought. Now the sad part. As the women was driving across the Evergreen Point Floating Bridge the drivers side front rim fractured around the bolt pattern. The subsequent crash killed both she and her baby. Follow up investigation found two more rims failing in the same mode. The bolts had been over torqued (alloy rims are more sensitive than steelL. Please be careful!! and be sure the mechanic working on such critical systems of your car is competent if you aren't performing the operations yourself. Chris Villani Fluke
rls@ihu1g.UUCP (r.l. schieve) (10/04/85)
....... > newly hired 'mechanic' remounted the wheels (alloy rims by the > way). Some where he got the notion that the wheel bolts needed > to be "torqued down". He did so with all the force the shops > impact wrench could muster. A job well done he thought. > Now the sad part. As the women was driving across the Evergreen > Point Floating Bridge the drivers side front rim fractured around > the bolt pattern. The subsequent crash killed both she and her > baby. Follow up investigation found two more rims failing in the > same mode. The bolts had been over torqued (alloy rims are more > sensitive than steelL. > > Please be careful!! and be sure the mechanic working > on such critical systems of your car is competent if you aren't > performing the operations yourself. > > Chris Villani > Fluke Alloy rims also usually go with crome lug nuts. Any mechanic using an impact wrench on my chrome plated lugs won't here the end of it until he gets me a new set. It is hard enough to keep them from rusting without someone tearing up the chrome. Also, with today's push for lighter cars, front disk brake rotors are not as heavy as they used to be. A friend with a 2 year old mid-sized Dodge had to have his rotors replaced because the lug nuts were tightened improperly. It seems that the uneven pressure contributed to the warping of his rotors, ruining his front brakes. Rick Schieve ....ihnp4!ihu1g!rls
phil@amdcad.UUCP (Phil Ngai) (10/07/85)
In article <1484@vax3.fluke.UUCP> gnosis@fluke.UUCP (Chris Villani) writes: >newly hired 'mechanic' remounted the wheels (alloy rims by the >way). Some where he got the notion that the wheel bolts needed >to be "torqued down". He did so with all the force the shops >impact wrench could muster. A job well done he thought. I said I use a torque wrench on my lug nuts. That means they get put on with a torque of exactly 45 foot-lbs. The reason I, and probably most mechanics, use a torque wrench is to AVOID over-tightening lug nuts. You don't need special equipment to act like a gorilla. Do I also have to explain that to tighten the nuts you turn clockwise and to loosen them you turn counter-clockwise? Cripes! (please, no jokes about digital watches. freshmen, please restrain yourselves.) -- Arthur Rudolph believed that technology is morally neutral and so, therefore, are those who create it. Phil Ngai +1 408 749-5720 UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil ARPA: amdcad!phil@decwrl.ARPA
phil@amdcad.UUCP (Phil Ngai) (10/07/85)
I think the saddest part of this story is that the person telling it
hasn't learned anything from the tragedy; he doesn't understand that
there is such a thing as a correct torque, not simply enough torque,
and the way to achieve it is by using a torque wrench.
--
Arthur Rudolph believed that technology is morally neutral and so,
therefore, are those who create it.
Phil Ngai +1 408 749-5720
UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil
ARPA: amdcad!phil@decwrl.ARPAgnosis@fluke.UUCP (Chris Villani) (10/09/85)
In article <4660@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes: >In article <1484@vax3.fluke.UUCP> gnosis@fluke.UUCP (Chris Villani) writes: >>newly hired 'mechanic' remounted the wheels (alloy rims by the >>way). Some where he got the notion that the wheel bolts needed >>to be "torqued down". He did so with all the force the shops >>impact wrench could muster. A job well done he thought. > >I said I use a torque wrench on my lug nuts. That means they get put >on with a torque of exactly 45 foot-lbs. The reason I, and probably >most mechanics, use a torque wrench is to AVOID over-tightening lug >nuts. You don't need special equipment to act like a gorilla. > >Do I also have to explain that to tighten the nuts you turn clockwise >and to loosen them you turn counter-clockwise? Cripes! My most humble apologies to Mr. Ngai. In no way did I intend to imply that he was in error when using his torque wrench as he had described. His article simply caused me to recall an incident in which a tightening procedure was done incorrectly with fatal results. I posted the 'Sad Story' as a general note of caution to us all. Also it was pointed out that I was in error when using the word "torque" (and its derivatives) when referring to a "tightening" procedure. I did so incorrectly while capitalizing on the fact that the two words are frequently used synonymously. I should have been more respectful of the net.auto subscribers level of technical discern- ment. In the future I will be more careful concerning the use of 'technical' terms. Oh, by the way Mr. Ngai I appreciate the lesson in rotational mechanics; I've been having trouble getting the lid off my peanutbutter jar. Chris Villani
aegroup@tekigm.UUCP (Dennis Ward) (11/20/85)
> In article <4660@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes: > >In article <1484@vax3.fluke.UUCP> gnosis@fluke.UUCP (Chris Villani) writes: > >> ....etc...... > > > >Do I also have to explain that to tighten the nuts you turn clockwise > >and to loosen them you turn counter-clockwise? Cripes! > > .....et.al..... > ..... Oh, by the way Mr. Ngai I appreciate the > lesson in rotational mechanics; I've been having trouble getting the > lid off my peanutbutter jar. > > Chris Villani I should hate to have either of you work on our cars. We have one car (a 1981 Renault 18i) that has no nuts, just four bolts per wheel that, yes, tighten clockwise and loosen ccw; another car (a 1984 Renault Encore) that has four nuts per wheel which tighten cw and loosen ccw; however, our third car (a 1966 Dodge Coronet) has five nuts per wheel that: tighten cw and loosen ccw -- on the right side or passenger side, and tighten ccw and loosen cw -- on the left or driver side. I do not know how many other makes of cars do this, but most Chrysler products (thru at least the 70's) had left hand threaded studs and nuts on the left hand of the car (driver side) and right hand threaded studs and nuts on the right hand of the car (passenger side). I have heard that Chrysler was not the only car maker to do this -- does anyone out there know who else did (does) this? From experience, I usually have to tell anyone working on the Dodge about this, as I have had several "mechanics" immediately try to remove the left hand nuts ccw and wonder why it does not work. Luckily, so far, no one has stripped any of the studs. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Renault: Volkswagen with a French accent and sex. (Compare engine compartments -- German efficiency vs French romanticism at its best.) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
toma@tekchips.UUCP (Tom Almy) (11/21/85)
In article <624@tekigm.UUCP> aegroup@tekigm.UUCP (Dennis Ward) writes: > > ... We have one car (a 1981 > Renault 18i) that has no nuts, just four bolts per wheel that, yes, tighten > clockwise and loosen ccw; another car (a 1984 Renault Encore) that has four > nuts per wheel which tighten cw and loosen ccw; however, our third car (a 1966 > Dodge Coronet) has five nuts per wheel that: tighten cw and loosen ccw -- on > the right side or passenger side, and tighten ccw and loosen cw -- on the left > or driver side. > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Renault: Volkswagen with a French accent and sex. (Compare engine > compartments -- German efficiency vs French romanticism at its best.) > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Yet another alternative: my Volkswagen Vanagon has 5 *bolts* per wheel on the front wheels, and 5 *nuts* per wheel on the back wheels. They all tighten clockwise and loosen ccw. Tom Almy
phil@amdcad.UUCP (Phil Ngai) (11/23/85)
In article <624@tekigm.UUCP> aegroup@tekigm.UUCP (Dennis Ward) writes: >> In article <4660@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes: >> >Do I also have to explain that to tighten the nuts you turn clockwise >> >and to loosen them you turn counter-clockwise? Cripes! > > I should hate to have either of you work on our cars. I don't know if you deliberately left out the way we got here or started reading in the middle. We were talking about Honda Civic brake rotors and why so many of them seem to get warped. I advanced the theory that they can be warped by an over zealous tightening of the wheel lug nuts, noting that I had experienced such problems on my Honda Civic. It was (and is) my first car so I have done a lot of learning on it. After I discovered torque wrenches and changed my brake rotors, I have not had any more problems with rotor warping. My new rotors have had 4 years of use on them, with some miles going downhill in the Yosemite National Park area. On one grade the brakes got so hot they started losing their effectiveness. (not downshifting on a down grade could be the subject of another lesson in how not to use your car) Despite this overheating, my rotors have remained unwarped. So I suggested others consider this cause of warping. I WAS NOT TALKING ABOUT YOUR CAR. No doubt the next time I talk about my car's sparkplugs some smart alec like you will whine that his diesel doesn't have any. Try to restrain yourself. -- Raise snails for fun and profit! Race them for amusement! Then eat the losers! Phil Ngai +1 408 749-5720 UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil ARPA: amdcad!phil@decwrl.dec.com