disk rotor choice

On Tue, 22 Mar 2011 16:44:47 -0500, "hls" > wrote:

>
>"Ashton Crusher" > wrote in message
.. .
>> On Sat, 19 Mar 2011 08:01:19 -0500, "hls" > wrote:
>>
>>>
>>>"dsi1" > wrote in message
...
>>>>> There are several factors at work here.
>>>>
>>>> My guess is that most car guys won't believe it.
>>>
>>>Im sure you are right.
>>
>>
>> Do you wash your new rotors in soap and water as the makers of the
>> rotors say is mandatory?
>
>I do wash them to get the rust preventative grease off of them. I have
>also used brake cleaner (largely methanol) in the past.

The experts say brake cleaner is not good enough. It won't remove the
metal particles left by the machining process, only soap and water
will. Supposedly it's important to remove the metal particles.

On Tue, 22 Mar 2011 16:50:23 -0500, "hls" > wrote:

>
>"Ashton Crusher" > wrote in message
.. .
>>
>> I've had genuine FORD rotors warp in 4000 miles of normal driving. And
>> the cheap china rotors go 20K without warping. I think it's mostly a
>> crap shoot.
>
>When you had the problem with the Ford rotors, was there any
>particular factor that you thought might have caused their early demise?
>

Nothing I could identify. It was a new vehicle and all work was done
by the dealer and I couldn't watch what they did. The original ford
rotors warped badly in 4K, the repairs (resurfaced or new, don't know
which they did) lasted for even less miles. Ever since I've used the
cheapest and they last much longer then the originals did. Ford
want's close to $150 per rotor, the cheapies are around $50. The
places that do my tires all use torque wrenches for final tightening.
Myself, I have been using just an impact anymore myself (did the
torque wrench thing for a while) and have not seen it cause a problem,
but I adjust it to a lower power setting so it won't over-torque.

>On several occasions, I have had rotors warp after having wheels
>rotated. These rotors had a year or two on them with no problem,
>but developed the warp within 2-3 weeks after the wheels were
>rotated and installed with an impact wrench and tork stix.

On 3/18/2011 2:36 PM, hls wrote:
>
> "dsi1" > wrote in message
> ...
>> On 3/18/2011 1:03 AM, George wrote:
>>> ('04 Cavalier) I need to replace the disk rotors. Everyone hereabouts
>>> seems to have two varieties: one at $22-ish, the other at $38. The $38
>>> ones have a longer warranty, but only for "defects".
>>>
>>> My guess is, the $38 ones are 'better' (more metal?); but, it could be
>>> just charging more for a pretty meaningless warranty. Does anyone know?
>>>
>>> Thanks,
>>> George
>>
>> Go the the store and ask to see both rotors. Buy the one with more
>> metal. In my case, I'd probably get the cheap rotors. My old Cavalier
>> was a great car and served me well. For me, only the cheapest parts
>> would go into that baby. :-)
>>
>> I read a startling article that said that the pulsating rotors are
>> actually caused by transference of pad material onto the surface of
>> the rotor at a molecular level which causes uneven braking. Beats the
>> heck out of me if this is true but if it is, then breaking-in the pads
>> could be critical. My understanding of the article is that applying
>> the brakes after heating them up will cause a visible imprint of the
>> pad onto the rotor. Weird stuff!
>
> I dont believe that. When I have chocked up the rotors in the brake
> lathe, there is definitely a significant warp. I have never seen much
> pad material transfer to the rotor surface, but then again I buy good
> pads.
>
> There are several factors at work here.

Here's the little article:

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

"Ashton Crusher" > wrote in message >
> The experts say brake cleaner is not good enough. It won't remove the
> metal particles left by the machining process, only soap and water
> will. Supposedly it's important to remove the metal particles.

Could be.. I have never noticed any difference, really, but then this
might be something I wouldn't notice. Certainly cheaper to use soap
and water.

On 03/23/2011 03:52 AM, dsi1 wrote:
> On 3/18/2011 2:36 PM, hls wrote:
>>
>> "dsi1" > wrote in message
>> ...
>>> On 3/18/2011 1:03 AM, George wrote:
>>>> ('04 Cavalier) I need to replace the disk rotors. Everyone hereabouts
>>>> seems to have two varieties: one at $22-ish, the other at $38. The $38
>>>> ones have a longer warranty, but only for "defects".
>>>>
>>>> My guess is, the $38 ones are 'better' (more metal?); but, it could be
>>>> just charging more for a pretty meaningless warranty. Does anyone know?
>>>>
>>>> Thanks,
>>>> George
>>>
>>> Go the the store and ask to see both rotors. Buy the one with more
>>> metal. In my case, I'd probably get the cheap rotors. My old Cavalier
>>> was a great car and served me well. For me, only the cheapest parts
>>> would go into that baby. :-)
>>>
>>> I read a startling article that said that the pulsating rotors are
>>> actually caused by transference of pad material onto the surface of
>>> the rotor at a molecular level which causes uneven braking. Beats the
>>> heck out of me if this is true but if it is, then breaking-in the pads
>>> could be critical. My understanding of the article is that applying
>>> the brakes after heating them up will cause a visible imprint of the
>>> pad onto the rotor. Weird stuff!
>>
>> I dont believe that. When I have chocked up the rotors in the brake
>> lathe, there is definitely a significant warp. I have never seen much
>> pad material transfer to the rotor surface, but then again I buy good
>> pads.
>>
>> There are several factors at work here.
>
> Here's the little article:
>
> http://www.stoptech.com/tech_info/wp...rakedisk.shtml

"in more than 40 years of professional racing, including the Shelby/Ford
GT 40s – one of the most intense brake development program in history -
I have never seen a warped brake disc"

indeed.

this is preceded by:
"presuming that the hub and wheel flange are flat and in good condition
and that the wheel bolts or hat mounting hardware is in good condition,
installed correctly and tightened uniformly and in the correct order to
the recommended torque specification"

you will find that in most cases, simply scraping surface rust off the
hub/wheel interface, applying a little antiseize, and correctly torquing
fasteners will cure most "warped" disks.

the fact that disk machining also "cures" is usually due to the
coincidence that cleaning is done at the same time.


--
nomina rutrum rutrum

On 03/22/2011 10:42 PM, Ashton Crusher wrote:
> On Tue, 22 Mar 2011 16:44:47 -0500, > wrote:
>
>>
>> "Ashton > wrote in message
>> ...
>>> On Sat, 19 Mar 2011 08:01:19 -0500, > wrote:
>>>
>>>>
>>>> > wrote in message
>>>> ...
>>>>>> There are several factors at work here.
>>>>>
>>>>> My guess is that most car guys won't believe it.
>>>>
>>>> Im sure you are right.
>>>
>>>
>>> Do you wash your new rotors in soap and water as the makers of the
>>> rotors say is mandatory?
>>
>> I do wash them to get the rust preventative grease off of them. I have
>> also used brake cleaner (largely methanol) in the past.
>
> The experts say brake cleaner is not good enough. It won't remove the
> metal particles left by the machining process, only soap and water
> will. Supposedly it's important to remove the metal particles.

disk pads contain abrasives that make "metal particles" completely
irrelevant. the reason to clean is so you get braking, not lubrication
when the brakes are applied the first time.


--
nomina rutrum rutrum