Brake shake with freshly machined rotors?

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N8N wrote:


I'm a crusty young guy that generally fits that description, but I imagine the vehicle freight charges would negate any savings :-) Also, find a crusty guy that doesn't get his crust on your car. Greasy isn't good on fabric or fenders. A 100% successful repair is one that addressed only the actual failed part(s), was done in a timely and convenient manner to the customer, and the car was returned at least as clean as it was brought in. Being nice to the customer really hinges on whether the customer was nice to begin with and isn't always included in the cost :-)
--
Toyota MDT in MO

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I always thought I was being a pretty decent customer to my guy. Maybe I'm wrong.
--
Tegger

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Tegger wrote:

I'm quite certain from your deportment displayed here that you have been a good customer. I was simply trying to explain why certain service providers act the way they do in this business. The 'everyone's buddy' 'yes man' BSer personality is rarely one who does his job honestly and competently in my experience.
--
Toyota MDT in MO

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Agree totally. The guy who does a good job and checks his work may, unfortunately make less money than the guy trying to beat the flat rate, putting on unnecessary parts, and doing that shoddily.
That is why it is important to find a good mechanic and support him or her. If you can trust him, and he knows his stuff, he is worth the money.
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There's an entire shop management approach to maximizing profit that says (I may have the percents wrong) every $100 in labor should be matched by $200 in parts largely because the markup on parts is about twice the markup on labor. These shops don't really want to do work that is mainly labor. Try and find a place that will replace a rear main seal.....much easier to find a place that will do a complete rebuild.
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Wow... This post sums up the sorry state of the industry quite well...

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Please explain to a "non-mechanic";
If the problem only shows up when the brakes are applied, I would be looking only at the braking system....
Faulty tires/balancing/rims would shake at driving speeds.
???
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You can machine warped rotors all you like, but it will not make any difference as far as the warping is concerned. The lathe will just follow the warp in the rotor and cut it the same, only thinner. Sounds like you need a new set of rotors. I would check the rear brakes to make sure they are operating as well, usually warped rotors result from either too much effort on the part of the front brakes trying to stop the car (excessive heat), or a mechanic overtorquing the wheel nuts upon reinstallation and unintentionally causing the warpage in the rotors.
How much pad lining is left on the front pads? Did they re-use the original pads, or install new ones? When they re-installed the caliper sliding pins, did they clean and then grease the pins and sliders so that the caliper slides freely?
Just my 2 cents, Sharky
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Absolute caca.. If you do it right, you can definitely machine the rotors, and if you reinstall correctly this can last a long time.
I suspect you had some bad experiences, Sharky.
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By the time you pay to machine two warped rotors, which are only going to be a tad better when reinstalled, you may as well purchase two new rotors that you know will be straight. Those warped rotors are not only warped, but have likely been subjected to extremely high temperatures and/or excessive stress on the lug nut studs from overtorquing. Not only are they warped, they more than likely have heat spots all over them. As far as I know, you cannot remove heat spots by machining the rotor. No, I haven't had that many bad experiences, but I can tell you for a fact, that it is much more cost effective in the long run to just purchase two new rotors. Buy one set of rotors the first time, as opposed to paying to machine an old set and then having to replace them much sooner down the road than you had wanted to, with a new set.
Another factor is whether you plan to keep the car long or short term. I tend to keep my vehicles long term, thus my reasoning for my reply.
Sharky
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Horse stuff...You really dont seem to know what you are talking about at all.
If the original rotors have enough meat left to allow them to be machined, and IF they are machined properly and installed properly, they will normally be okay.
Buying a new rotor is likely to give you a good platform, but not necessarily. They should be surfaced, in most cases, to be sure the pads seat in well, and they CAN be warped (directly from the factory in China).
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Believe what you wish. If you think using an overheated, overtorqed, warped rotor that has likely been pushed over its' limit more than once, and then you take that rotor and make the surface even thinner than it was, how can that possibly be any better than buying new? Nevermind the fact that the metal properties of the rotor have already been effected from excessive heat. And knowing that it probably cost you 2/3rds of buying new in the first place. Personally, I don't believe in doing things half-assed, nor do I have the extra time or desire to have to re-do the same job 6 months down the road. As far as buying new rotors and them already being warped, I don't buy no-name parts in the $20 or less bin. You can buy a medium to high quality rotor and still pay under $75 each, in most cases. More than likely it was made right here in NA and not overseas.
Listen, if I had a machine in my shop at my disposal, of course I would resurface the old rotors, so long as they met the requirements to do so. But in the middle of a brake job, with the front-end of my car in pieces, I am not going to try and find a way to the closest shop with a lathe and then turn around and pay anywhere from $20 to $50 per rotor to have them machined. For one, not everyone has a second car in the driveway to be able to do that. Secondly, you have no idea how that rotor is going to turn out. Even an expert machinist may not be able to cut it perfectly. And if he doesn't, that's the same as taking a lighter to the money you just spent on that used rotor. No, I'd rather just pick up a pair of rotors while I'm already at the parts store to get pads and whatever else I need. That way, I have two new rotors sitting beside me when the brakes are ready to go back together.
I'm talking about cost in the long run and life of the used rotor. It makes much more sense to buy two new rotors as opposed to machining used/warped rotors that will probably last under a year. The last time I had rotors/drums machined, it cost me about $30-$40 per rotor/drum. For most domestic vehicles I have owned in the last 10 years, add ~$25 or less per unit and you have new, with warranty. What happens when that used rotor fails a second time around, and you have no option of machining it? Don't tell me you search all the junk yards for a used pair to resurface?
Sharky
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Maybe you have had some bad luck. I certainly would support that some rotors shouldn't be machined and should be replaced with new.
But not every occasion of warpage demands a new rotor.
Machining at the local shop here is $15 a rotor. New rotors cost varies a lot.
A lot of mechanics just replace caliper and rotor, because they believe the cost is equal or less than doing a good renovation job (and it MIGHT be), because they dont want comebacks of the type you describe, and because the customer pretty much has to pay whatever the case.
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no one who is up to date recommends resurfacing new rotors. When you get a set of heads do you send them out to be milled???
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Nope. By surfacing, I do not mean machining. Perhaps that is the issue.
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If that's what you mean then sure, they should have the proper surface finish on them. All the replacement rotors I've purchased have already been given a proper non-directional finish by whoever made them.
One thing a lot of people don't do that the repair manuals say is a MUST is to wash the new rotors (or old freshly machined ones) with soap and water. Supposedly that's the only way to get the fine metal dust from the machining/surfacing operation out of the pores. If you don't get that metal dust out then you may develop some sort of non-uniformity in the surface soon after they go in service.
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I also think they should be washed. Soap and water would be fine, or methylalcohol as in spray brake cleaners. I suspect that most manufacturers apply some sort of filming corrosion inhitor to reduce the rusting of shelf stock, and if so that should probably be removed.
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Ashton Crusher wrote:

if I were going to "build it to last forever" I definitely would. And ported, gasket matched, etc.
nate
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Sharky wrote:

50-75% pad left, original pads, and no idea if they lubed it. If I'd done it myself I'd have lubed it, but I don't feel like working on company car myself. I did change the oil when I first got it because it was due on time but not on mileage (so I couldn't get them to pay for it) and I was so paranoid, even though I've never screwed up an oil change in my life.
nate
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wrote:

Is this thing still under warranty? If not, why?
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