a brake question, is it true?

This message is not archived
 >> Stay informed about: a brake question, is it true? 

On Thu, 28 Jun 2007 05:40:57 GMT, Bruce L. Bergman
<blnospambergman RemoveThis @earthlink.invalid> wrote:

>The rotors do not need to be turned if they are worn flat and even,
>and not warped or scored by the pads.
>
> You can usually get away with not turning the rotors once, but by
>the time the second set of brake pads are gone the rotors are grooved
>enough where they have to be turned. And if they are worn to where
>they will be under the minimum safe thickness after machining, or
>warped, you get new rotors.


How long the rotors last depends more on the pad than anything. If you
use hard OEM type pads you may only get a few pad changes out of them
but if you use a bit softer aftermarket pads they can last a very long
time. I have gone over 200K miles on a set of rotors more than once.
Also I do not beleive in turning rotors for a few reasons too. First
if they are warped, turning them reduces the thickness and surface
grain structure (because depth of cut varies on a warped rotor) and
second just general turning of them reduces thickness and increase
tendacy to warp too because it reduces thermal mass and reduced mass
means that rotors will get a bit hotter in harder stops because though
some energy is disapatted into air stream, most of it is stored during
a hard sudden stop to be disapated later. A thinner lighter rotor can
absorb less heat before fade or possible warpage than a thicker
heavier one.
-----------------
TheSnoMan.com
 >> Stay informed about: a brake question, is it true? 

But aren't rotors engineered/designed to be turned? At least once, right?

We (engineers) don't typically put "extra" somewhere unless it is meant to
be there. Management will run a cost analysis and have us reduce and reduce
until (eventually) we have trimmed all the fat. (Sometimes we trim too much,
and there isn't enough meat left on the bones! But we try to correct that as
soon as possible.)

I think, if there is enough steel on those rotors for them to be turned once
safely, it was engineered to be that way. The thinner, lighter rotor will
certainly be more prone to fade and warpage than a thicker rotor, but as
long as the rotor is within the specs, the average mechanic should be able
to rest assured that the rotor was engineered to handle it.

"SnoMan" wrote:
>
> How long the rotors last depends more on the pad than anything. If you
> use hard OEM type pads you may only get a few pad changes out of them
> but if you use a bit softer aftermarket pads they can last a very long
> time. I have gone over 200K miles on a set of rotors more than once.
> Also I do not beleive in turning rotors for a few reasons too. First
> if they are warped, turning them reduces the thickness and surface
> grain structure (because depth of cut varies on a warped rotor) and
> second just general turning of them reduces thickness and increase
> tendacy to warp too because it reduces thermal mass and reduced mass
> means that rotors will get a bit hotter in harder stops because though
> some energy is disapatted into air stream, most of it is stored during
> a hard sudden stop to be disapated later. A thinner lighter rotor can
> absorb less heat before fade or possible warpage than a thicker
> heavier one.
> -----------------
> TheSnoMan.com
 >> Stay informed about: a brake question, is it true? 

I think they are over charging you for sure, and they may not be checking
your brake pads as thoroughly as they lead you to believe.

I'd recommend taking your vehicle to some place that specializes in brakes
to have them checked.

"harry" asked:
> My 2004 Sequoia just had its second sets of brake pads replaced today with
> resurfacing!
> When the first time I had the pad replaced, I was told by dealer that the
> rotor needs resurfacing because the pad was down too low (15% or so).
> So I kept in mind that I will replace the pad before it hurts the rotor.
> No matter how often I asked the dealer, they would tell me that the pad is
> absolutely fine until next oil change.
> Well, I changed the pad by dealer and they still claimed that the rotor
> needs $180 resurfacing on top of $130 front brake pad.
>
> Are they BSing me again? I can't believe they want to charge me $470 for
> front and rear brake pads!
>
 >> Stay informed about: a brake question, is it true? 

On Thu, 28 Jun 2007 13:16:44 GMT, "jp2express" <joe.RemoveThis@mail.com> wrote:

>But aren't rotors engineered/designed to be turned? At least once, right?
>
>We (engineers) don't typically put "extra" somewhere unless it is meant to
>be there. Management will run a cost analysis and have us reduce and reduce
>until (eventually) we have trimmed all the fat. (Sometimes we trim too much,
>and there isn't enough meat left on the bones! But we try to correct that as
>soon as possible.)
>
>I think, if there is enough steel on those rotors for them to be turned once
>safely, it was engineered to be that way. The thinner, lighter rotor will
>certainly be more prone to fade and warpage than a thicker rotor, but as
>long as the rotor is within the specs, the average mechanic should be able
>to rest assured that the rotor was engineered to handle it.


I would not be so bold. Rotors are getting to be a automatic change
with brake jobs with some models and pad combos. Make it cheaper and
lighter is the moto today and that means less material. Back in 70's
when disc brakes first came out there was some serious rotors on them.
Over the years they have cheaped them up. Yes they have turn limits
but when you turn them there is less mass in them to absord the heat
and disapate it and thinner rotor warp easier because less material to
deal with heat and stress. To assuming it is just fine is streching it
especailly on LD vehicle as there is a very small level of reserve
engineering in them with auto makers trying to squeeze every penny of
profit out of them and part to repair them too.
-----------------
TheSnoMan.com
 >> Stay informed about: a brake question, is it true? 

"SnoMan" <admin.RemoveThis@snoman.com> wrote in message
news:sh9883h7mbq7ag015upsmpc50r5d2e2qqn@4ax.com...
> On Thu, 28 Jun 2007 13:16:44 GMT, "jp2express" <joe.RemoveThis@mail.com> wrote:
>
>>But aren't rotors engineered/designed to be turned? At least once, right?
>>
>>We (engineers) don't typically put "extra" somewhere unless it is meant to
>>be there. Management will run a cost analysis and have us reduce and
>>reduce
>>until (eventually) we have trimmed all the fat. (Sometimes we trim too
>>much,
>>and there isn't enough meat left on the bones! But we try to correct that
>>as
>>soon as possible.)
>>
>>I think, if there is enough steel on those rotors for them to be turned
>>once
>>safely, it was engineered to be that way. The thinner, lighter rotor will
>>certainly be more prone to fade and warpage than a thicker rotor, but as
>>long as the rotor is within the specs, the average mechanic should be able
>>to rest assured that the rotor was engineered to handle it.
>
>
> I would not be so bold. Rotors are getting to be a automatic change
> with brake jobs with some models and pad combos. Make it cheaper and
> lighter is the moto today and that means less material. Back in 70's
> when disc brakes first came out there was some serious rotors on them.
> Over the years they have cheaped them up. Yes they have turn limits
> but when you turn them there is less mass in them to absord the heat
> and disapate it and thinner rotor warp easier because less material to
> deal with heat and stress. To assuming it is just fine is streching it
> especailly on LD vehicle as there is a very small level of reserve
> engineering in them with auto makers trying to squeeze every penny of
> profit out of them and part to repair them too.


On the other hand, if the rotor is stamped with a minimum specification, and
the rotors can be turned and still remain thicker than the spec, then it is
perfectly okay to turn them.

Engineers are generally a pretty bright group of people, and they know about
mass and heat dissipation and wear, and lots of stuff like that. If the
engineers say that a rotor is servicable at <whatever>, and the rotor is
..050 thicker than that, and can be made straight by removing .020 of
material, then logic says it is still a servicable part. Will it last to the
next service interval? That's difficult to say because there are far too
many variables -- it is possible that brand new rotors will not last to the
next service interval, and it's possible that a rotor will exceed a service
life of two intervals.

I hesitate to buy into your argument that rotors have been cheapened -- this
implies they are made worse, when the only thing that is true is they are
made differently. Different might be better, but because there is less
material, you automatically toss out inflamatory terms like "cheapened."
 >> Stay informed about: a brake question, is it true? 

"jp2express" <joe.DeleteThis@mail.com> wrote in message
news:GzOgi.27296$YL5.13549@newssvr29.news.prodigy.net...
>I think they are over charging you for sure, and they may not be checking
>your brake pads as thoroughly as they lead you to believe.
>

Oreilley's only charges about $10 to turn rotors. How many rotors do you
have! They DEFINATELY ripped you off on the rotor turning!

> I'd recommend taking your vehicle to some place that specializes in brakes
> to have them checked.
>

Ditto!

> "harry" asked:
>> My 2004 Sequoia just had its second sets of brake pads replaced today
>> with resurfacing!
>> When the first time I had the pad replaced, I was told by dealer that the
>> rotor needs resurfacing because the pad was down too low (15% or so).
>> So I kept in mind that I will replace the pad before it hurts the rotor.
>> No matter how often I asked the dealer, they would tell me that the pad
>> is absolutely fine until next oil change.
>> Well, I changed the pad by dealer and they still claimed that the rotor
>> needs $180 resurfacing on top of $130 front brake pad.
>>
>> Are they BSing me again? I can't believe they want to charge me $470 for
>> front and rear brake pads!
>>
>
>
>
 >> Stay informed about: a brake question, is it true? 

"harry" <harry_liuNOSPAM RemoveThis @lcc.com> wrote in message
news:tcGgi.652301$2Q1.464450@newsfe16.lga...
> My 2004 Sequoia just had its second sets of brake pads replaced today with
> resurfacing!
> When the first time I had the pad replaced, I was told by dealer that the
> rotor needs resurfacing because the pad was down too low (15% or so).
> So I kept in mind that I will replace the pad before it hurts the rotor.
> No matter how often I asked the dealer, they would tell me that the pad is
> absolutely fine until next oil change.
> Well, I changed the pad by dealer and they still claimed that the rotor
> needs $180 resurfacing on top of $130 front brake pad.
>
> Are they BSing me again? I can't believe they want to charge me $470 for
> front and rear brake pads!
>

This is why it is good to take auto shop in high school.

You are facing one of the most basic of car repairs, and a repair that can
easily be done at home. Pads run to about $50 per axle set, and rotors are
generally $50 each. You can pay less, but you can see that an axle set of
rotors and pads should cost about $150 for parts, $300 for parts for both
axles. You can easily find deals where these parts come in for less, but the
point I'm making is that you can buy First Rate stuff and put the parts in
yourself faster and cheaper than the trip to the mechanic.

If the rotors are in good condition, they can be machined true for about $10
each, if they are not in good shape, they can be replaced for under $100 for
the pair of them. (And, one should always replace brake components in Axle
Sets.)

I bought a complete set of pads and rotors for my '94 BMW 3 Series on eBay
for about $170. I had to have machine work done to the rotors for an
additional $30 -- I complained about the needed machine work, and they sent
me another set of rotors for free, so for less than the $300 I told you
about earlier, I got a complete set of rotors and pads, another set of front
rotors, and all of the machine work needed to make them work right.

All because I took auto shop in high school.

This is not a job that requires auto shop in high school, but one does need
to know which end of the screwdriver is the handle.
 >> Stay informed about: a brake question, is it true? 

Rotors are a consumable item. Sooner or later they will need to be
replaced. Yes, some can be resurfaced, and some are too thin and too
soft & worn to resurface. I prefer to have them turned on the
car...some shops have the brake lathe to do this. Turning the rotor off
the car is OK if the shop mounts it on the lathe correctly and if the
rotor mounts on the hub OK. I like less than 0.007" runout from my rotors.
http://hunterengineering.com/pub/product/lathe/5071T/index.htm

Anyone can learn to inspect their own brakes and rotors. I agree with
Bruce about some of the better shops. Other shops pad the job just to
pad the bill.

There is a big difference in the quality of the cast iron and between
the cheapest rotors and the best (all are cast iron). Don't go cheap
unless you're planning on selling the rig in weeks.


Ken



harry wrote:
> My 2004 Sequoia just had its second sets of brake pads replaced today with
> resurfacing!
> When the first time I had the pad replaced, I was told by dealer that the
> rotor needs resurfacing because the pad was down too low (15% or so).
> So I kept in mind that I will replace the pad before it hurts the rotor. No
> matter how often I asked the dealer, they would tell me that the pad is
> absolutely fine until next oil change.
> Well, I changed the pad by dealer and they still claimed that the rotor
> needs $180 resurfacing on top of $130 front brake pad.
>
> Are they BSing me again? I can't believe they want to charge me $470 for
> front and rear brake pads!
>
>
 >> Stay informed about: a brake question, is it true? 

"Jeff Strickland" <crwlr DeleteThis @verizon.net> wrote in message
news:SZzhi.170$q12.124@trnddc08...
>
> "harry" <harry_liuNOSPAM DeleteThis @lcc.com> wrote in message
> news:tcGgi.652301$2Q1.464450@newsfe16.lga...
>> My 2004 Sequoia just had its second sets of brake pads replaced today
>> with resurfacing!
>> When the first time I had the pad replaced, I was told by dealer that the
>> rotor needs resurfacing because the pad was down too low (15% or so).
>> So I kept in mind that I will replace the pad before it hurts the rotor.
>> No matter how often I asked the dealer, they would tell me that the pad
>> is absolutely fine until next oil change.
>> Well, I changed the pad by dealer and they still claimed that the rotor
>> needs $180 resurfacing on top of $130 front brake pad.
>>
>> Are they BSing me again? I can't believe they want to charge me $470 for
>> front and rear brake pads!
>>
>
> This is why it is good to take auto shop in high school.
>
> You are facing one of the most basic of car repairs, and a repair that can
> easily be done at home. Pads run to about $50 per axle set, and rotors are
> generally $50 each. You can pay less, but you can see that an axle set of
> rotors and pads should cost about $150 for parts, $300 for parts for both
> axles. You can easily find deals where these parts come in for less, but
> the point I'm making is that you can buy First Rate stuff and put the
> parts in yourself faster and cheaper than the trip to the mechanic.
>
> If the rotors are in good condition, they can be machined true for about
> $10 each, if they are not in good shape, they can be replaced for under
> $100 for the pair of them. (And, one should always replace brake
> components in Axle Sets.)
>
> I bought a complete set of pads and rotors for my '94 BMW 3 Series on eBay
> for about $170. I had to have machine work done to the rotors for an
> additional $30 -- I complained about the needed machine work, and they
> sent me another set of rotors for free, so for less than the $300 I told
> you about earlier, I got a complete set of rotors and pads, another set of
> front rotors, and all of the machine work needed to make them work right.
>
> All because I took auto shop in high school.
>

I just helped out my dad when I was too young to drive.

> This is not a job that requires auto shop in high school, but one does
> need to know which end of the screwdriver is the handle.
 >> Stay informed about: a brake question, is it true?