Brake shake with freshly machined rotors?

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Yes and heat I will believe. It could drive the rotor to wobble enough that the pads can't follow. But that would take a fair amount of heat to warp a hunk of steel that heavy.

Baloney. I'd like to know how many wheels I've done over the years. I'm not running a shop by any means but I've done a lot of work on vehicles and machinery. I'll argue to the cows come home on this one. Heat sure, but that's an entirely different matter.

They can believe it they wish. Old wives tale. I don't. Suspect it's any easy way to convince people to replace with new. Anyone without real experience with the tools can't argue. And the shop is clear. And that's the most important part for a shop. You can't offend a customer with new parts.

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It's more fun to argue about brake system flushes and how brake fluid is constantly sucking up water until your MC starts overflowing. --Vic
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wrote in message

lol
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The "requirement" for a torque wrench came along with the popularity of alloy wheels. Rattling lug nuts on with an impact was considered to be unhealthy for the alloy wheel. I've heard of cases of broken wheels, but I've never seen one. I believe it might be much easier to create an oblong hole in an alloy wheel than to break the wheel.
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You can do what you want. I am telling you what I have found, and you can take it or leave it. No hard feelings.
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HLS wrote:

Another Bad one for warped rotors from air hammers is Chrysler Jeep products, they warp bad and easy.
Mike 2000 Cherokee Sport 86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00 'New' frame and everything else in '09. Some Canadian Bush Trip and Build Photos: http://mikeromainjeeptrips.shutterfly.com
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Somebody needs to give me the theory behind this phenonomon. The rim itself has nothing to do with it. The only device which comes into contact with the rotor is the caliper and pads. The piston side of the caliper should move with fairly little pressure so scratch that idea. The whole caliper should move if there were pressure on the outer side. Besides it would take a fair amount of pressure to bend the rotor. Only if the rotor were loose and something got behind to cause wobble after tightening then yes. The run out of the rotor would wear the rotor surfaces on opposite sides and opposite diameters, with consequent uneven thickness. Most of the rotors take some effort to remove after a few years of service so I don't see tire service causing problems. Finding a hub improperly machined from the factory is very unlikely given today's manufacturing standards. Removing a rim for tire service is not going to change the dynamics of the rotor.
Somebody has to show me an actual case before I'll buy it. I've been around too long.
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It has everything to do with 'it'... Remember, this is with alloy wheels, not steel ones. There's a reason: steel rims are rather flexible, alloy ones are not, the center hub is much more rigid.

Oh, not in 99% of the vehicles on the road. Almost all have the rotor sandwiched between the rim and the hub. Check yours, and you'll see it. Exceptions are very exotic ones such as the Hummer H1 (inboard brakes on all for corners), the vette, some Jaugar models, and some high-end sports cars. Most common vehicles have rotors sandwiched just as described.

Humm...

Virtually everything above is either outright wrong, or misstated.

How long you have been around is insignificant if you stopped learning at 15. But, hell, in your world everyone else is wrong and you are right.
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wrote:

OK so how does a rim affect the rotor in either case? As you state most are sandwiched between. Forget exotic vehicles. How many of us drive such things anyway?

I know that.

You don't say WHAT's wrong.

On any of the common wheels most of us drive I've not seen it yet.
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I've had it happen to an ordinary audi with alloy wheels about 15 years ago. I had new tires installed and the shop had hammered the wheels back apparently on full blast with the impact wrench, and I had a terrible shimmy.
I tried to torque the wheels properly at home, but could not get the bolts on one of the wheels loose. I cracked a socket trying to undo the bolts.
I went back to the shop and with the long hose they had on the IW they could not get the bolts loose without waiting for the compressor to build full pressure in the tank. When they torqued the wheel properly the shimmy was gone.
I always hand torque the wheels after this and I have never had a problem with it again.
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wrote:

Obviously the wheel was mounted crooked. But the rotor wasn't damaged and that's my point. But any reasonable person on a wrench should know enough not to tighten one bolt to extreme. It doesn't require a torque wrench IMHO. Of course as I've pointed out earlier in the thread any jockey may do the job using a torque wrench and it relieves the shop of any consequences.
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No it was not. Just properly tightening the bolts one at a time to the proper torque was enough to fix the problem. The wheel was not removed, which would have been needed had the wheel been put on crooked.
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writes:

Not true. It would only require to loosen each lug nut a bit and retighten them. I agree with labatyd - your experience is not the same as what is being discussed.
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wrote:

Just for the hell of it I'm going to take off (in turn) each front wheel of my vehicles with disc brakes and retighten the rim to try to achieve what you guys are telling me. I'll be watching very closely for any changes. I don't expect any.
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If you retighten with an ordinary socket and BO bar, you probably wont. The human brain and sense of feel will give an even slightly experienced person some control.
Slam it on with an impact wrench, all rotored wheels, as if you were a tire monkey. Watch it for a month or two. You may be lucky and you may not.
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Yeahbut that's not what's being discussed here. That's an extreme. I realize you say you've seen this and I take your word for that, but I haven't. Here's another side of this discussion - just the other day I had to have a tire replaced. The mechanic threw the wheel back on the car and ran it up with his impact - "hammering" each lug. But... his gun is set very low, so the torque being applied to each lug is well under the torque spec. To hear it, it sounds like he's just hammering the lug nuts on. He grabbed the torque wrench when that was done and proceeded to get around a quarter turn (or maybe a bit less), on each lug nut.
Those of us that don't use a torque wrench (I have used them, but do not use them on any regular basis), have put them on with our impacts, and then drove problem free for more than a month or two. That's the point of this discussion - lots of folks don't use a torque wrench and have no problems, either short term or long term.
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1. Goto barn. 2. Door was left open. 3. Check horse 4. Horse missing. 5. Close door. 6. Problem solved!
Not much of a test, there is nothing that says that the warpage would correct itself if you did that. Only some evidence that in some cases it helps.
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wrote:

Where does the warpage come from? You're sandwiching steel between steel. There is nothing to give or bend. No gasket material between like installing a head on an engine. If something got between then I can understand the claim.
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They can both bend. When you tighten a lugnut to 100 ftlbs, it can apply thousands of PSI to the rotor/hub, more if using an impact wrench. Steel, cast iron etc all bend easily under such forces. HTH Ben
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