Ceramic Brake Pads - '99 T & C

Follow up to an earlier post.

Well I ordered some Akebono ProAct ceramic pads for my '99 and I
installed them today. What a difference! The growling and minor
pulsing has gone. the braking action is smooth and uniform at all
speeds. I hope it also reduces the dusting that was occuring with
those junk pads that were on there.

Frank

I had to have the rotors and pads replaced at 27K miles. Is this the norm?
They did pulsate but at this many miles? Is it because I didn't use the car
for extended periods of time? I put 27K miles in 4 years.

Ken





"Frank Boettcher" > wrote in message
...
> Follow up to an earlier post.
>
> Well I ordered some Akebono ProAct ceramic pads for my '99 and I
> installed them today. What a difference! The growling and minor
> pulsing has gone. the braking action is smooth and uniform at all
> speeds. I hope it also reduces the dusting that was occuring with
> those junk pads that were on there.
>
> Frank

Same need on a '98 Grand Caravan -- at five years and 38,000 miles,
along with front and rear struts/shocks, starter and serpentine belt
tensioner.

Not until all the OEM failures were replaced did the van work reliably.


NJ Vike wrote:
> I had to have the rotors and pads replaced at 27K miles. Is this the norm?
> They did pulsate but at this many miles? Is it because I didn't use the car
> for extended periods of time? I put 27K miles in 4 years.
>
> Ken
>
>
> "Frank Boettcher" > wrote in message
> ...
>
>>Follow up to an earlier post.
>>
>>Well I ordered some Akebono ProAct ceramic pads for my '99 and I
>>installed them today. What a difference! The growling and minor
>>pulsing has gone. the braking action is smooth and uniform at all
>>speeds. I hope it also reduces the dusting that was occuring with
>>those junk pads that were on there.
>>
>>Frank

That's sad. I'm starting to wonder about keeping my existing car and
purchasing a new 300C. Perhaps it's time to look elsewhere?



"News" > wrote in message
...
> Same need on a '98 Grand Caravan -- at five years and 38,000 miles, along
> with front and rear struts/shocks, starter and serpentine belt tensioner.
>
> Not until all the OEM failures were replaced did the van work reliably.
>
>
> NJ Vike wrote:
>> I had to have the rotors and pads replaced at 27K miles. Is this the
>> norm? They did pulsate but at this many miles? Is it because I didn't use
>> the car for extended periods of time? I put 27K miles in 4 years.
>>
>> Ken
>>
>>
>> "Frank Boettcher" > wrote in message
>> ...
>>
>>>Follow up to an earlier post.
>>>
>>>Well I ordered some Akebono ProAct ceramic pads for my '99 and I
>>>installed them today. What a difference! The growling and minor
>>>pulsing has gone. the braking action is smooth and uniform at all
>>>speeds. I hope it also reduces the dusting that was occuring with
>>>those junk pads that were on there.
>>>
>>>Frank

NJ Vike wrote:
> I had to have the rotors and pads replaced at 27K miles. Is this the norm?
> They did pulsate but at this many miles? Is it because I didn't use the car
> for extended periods of time? I put 27K miles in 4 years.

One thing is that the lug nuts have to be torqued to spec, which is
really tight- for mine, 100 ft/lb. The wheels clamp the rotors, and if
the lug nuts aren't tight enough, the rotors warp.

This applies generally to vehicles with disc brakes, it's not make or
model specific. I got this bit of wisdom from a pro.
-Paul

wrote:
> NJ Vike wrote:
>
>>I had to have the rotors and pads replaced at 27K miles. Is this the norm?
>>They did pulsate but at this many miles? Is it because I didn't use the car
>>for extended periods of time? I put 27K miles in 4 years.
>
>
> One thing is that the lug nuts have to be torqued to spec, which is
> really tight- for mine, 100 ft/lb. The wheels clamp the rotors, and if
> the lug nuts aren't tight enough, the rotors warp.
>
> This applies generally to vehicles with disc brakes, it's not make or
> model specific. I got this bit of wisdom from a pro.

Interesting. The conventional wisdom for years was just the opposite -
that overtightening was the cause of rotor "warping." However, I've
read an article or two more recently that suggests that the issue isn't
warping of the rotor (which can easily be verified with a dial
indicator), but rather uneven accumulation of pad material around the
disk and/or rust patches. This causes the coefficient of friction to
vary around the circumference of the disk causing the pulsing during
brake application. I'm becoming more and more convinced that this is
the real cause more often then not.

The reason I think this is that the cure that folks who claim this
suggest seems to work and it certainly wouldn't fix a truly warped
rotor. The cure is several successive hard stops as I recall, somewhat
similar to breaking in new pads. This heats up the disk and
redistributes the pad residue and cleans off any uneven rust. I've done
this a couple of times on my minivans with good success.


Matt

Matt Whiting wrote:
> wrote:
>
>> NJ Vike wrote:
>>
>>> I had to have the rotors and pads replaced at 27K miles. Is this the
>>> norm?
>>> They did pulsate but at this many miles? Is it because I didn't use
>>> the car
>>> for extended periods of time? I put 27K miles in 4 years.
>>
>>
>>
>> One thing is that the lug nuts have to be torqued to spec, which is
>> really tight- for mine, 100 ft/lb. The wheels clamp the rotors, and if
>> the lug nuts aren't tight enough, the rotors warp.
>>
>> This applies generally to vehicles with disc brakes, it's not make or
>> model specific. I got this bit of wisdom from a pro.
>
>
> Interesting. The conventional wisdom for years was just the opposite -
> that overtightening was the cause of rotor "warping."

You don't hear the "undertightened" theory too much. I suppose you
could argue that undertightening will mean less intimate contact between
rotor and hub so that the rotor heat won't be able to get as much
cooling by conduction into the hub - and that in fact could be a
contributing factor. That's why there is a *correct* torque value - not
just a max. or min.

> However, I've
> read an article or two more recently that suggests that the issue isn't
> warping of the rotor (which can easily be verified with a dial
> indicator), but rather uneven accumulation of pad material around the
> disk and/or rust patches. This causes the coefficient of friction to
> vary around the circumference of the disk causing the pulsing during
> brake application. I'm becoming more and more convinced that this is
> the real cause more often then not.
>
> The reason I think this is that the cure that folks who claim this
> suggest seems to work and it certainly wouldn't fix a truly warped
> rotor. The cure is several successive hard stops as I recall, somewhat
> similar to breaking in new pads. This heats up the disk and
> redistributes the pad residue and cleans off any uneven rust. I've done
> this a couple of times on my minivans with good success.

I've come to that same conclusion and have posted about it several times
here and elsewhere. See my second post from just two days ago in this
thread: http://300mclub.org/forums/viewtopic.php?t=11452.

However, there are some pads that are so bad that the "several succesive
hard stops" trick just causes thicker uneven layers to deposit - I had
that happen last year with a set of very gummy ceramic pads.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

Bill Putney wrote:
> Matt Whiting wrote:
>
>> wrote:
>>
>>> NJ Vike wrote:
>>>
>>>> I had to have the rotors and pads replaced at 27K miles. Is this the
>>>> norm?
>>>> They did pulsate but at this many miles? Is it because I didn't use
>>>> the car
>>>> for extended periods of time? I put 27K miles in 4 years.
>>>
>>>
>>>
>>>
>>> One thing is that the lug nuts have to be torqued to spec, which is
>>> really tight- for mine, 100 ft/lb. The wheels clamp the rotors, and if
>>> the lug nuts aren't tight enough, the rotors warp.
>>>
>>> This applies generally to vehicles with disc brakes, it's not make or
>>> model specific. I got this bit of wisdom from a pro.
>>
>>
>>
>> Interesting. The conventional wisdom for years was just the opposite
>> - that overtightening was the cause of rotor "warping."
>
>
> You don't hear the "undertightened" theory too much. I suppose you
> could argue that undertightening will mean less intimate contact between
> rotor and hub so that the rotor heat won't be able to get as much
> cooling by conduction into the hub - and that in fact could be a
> contributing factor. That's why there is a *correct* torque value - not
> just a max. or min.

Unless the lug nuts were loose enough to let the wheel wobble, I don't
think heat transfer will be much affected. And I'm pretty sure that the
fastener torque value has everything to do with ensuring the parts
remain fastened and nothing to do with heat transfer. You want the
studs stretched enough to keep the lug nuts from coming loose and to
ensure that the wheel stays tight against the hub under expected loads,
but not stretched so far that the normal loads will cause the stud to
exceed is elastic limit.


>> However, I've read an article or two more recently that suggests that
>> the issue isn't warping of the rotor (which can easily be verified
>> with a dial indicator), but rather uneven accumulation of pad material
>> around the disk and/or rust patches. This causes the coefficient of
>> friction to vary around the circumference of the disk causing the
>> pulsing during brake application. I'm becoming more and more
>> convinced that this is the real cause more often then not.
>>
>> The reason I think this is that the cure that folks who claim this
>> suggest seems to work and it certainly wouldn't fix a truly warped
>> rotor. The cure is several successive hard stops as I recall,
>> somewhat similar to breaking in new pads. This heats up the disk and
>> redistributes the pad residue and cleans off any uneven rust. I've
>> done this a couple of times on my minivans with good success.
>
>
> I've come to that same conclusion and have posted about it several times
> here and elsewhere. See my second post from just two days ago in this
> thread: http://300mclub.org/forums/viewtopic.php?t=11452.
>
> However, there are some pads that are so bad that the "several succesive
> hard stops" trick just causes thicker uneven layers to deposit - I had
> that happen last year with a set of very gummy ceramic pads.

Every rule has its exception! :-)

Matt

Matt Whiting wrote:

>
> Unless the lug nuts were loose enough to let the wheel wobble, I don't
> think heat transfer will be much affected. And I'm pretty sure that the
> fastener torque value has everything to do with ensuring the parts
> remain fastened and nothing to do with heat transfer. You want the
> studs stretched enough to keep the lug nuts from coming loose and to
> ensure that the wheel stays tight against the hub under expected loads,
> but not stretched so far that the normal loads will cause the stud to
> exceed is elastic limit.
>

Yes, I believe your analysis is correct. There's no rust or anything
but shiny metal on the friction areas of my rotors, so foreign material
on there is not the cause.

In my case, my brakes worked smoothly, then I removed my front wheels
and just used my impact wrench to reinstall the lugnuts. I remember
thinking "man, these lugnuts are tight" when I took them off. I had to
use a breaker bar to get them loose. I torque things like head bolts,
but have never bothered to torque lug nuts.

Soon after, my brake pedal started pulsating. Same rotors, same brake
pads. So I'm convinced the pro who explained the cause to me was
correct. There's a reason why that torque spec is so high.

So try it folks- torque the lug nuts to spec. It's the right thing to
do, and it's an easy and cheap solution if it works. Then get back to
us and tell us if it worked.

-Paul

wrote:


> ...In my case, my brakes worked smoothly, then I removed my front wheels
> and just used my impact wrench to reinstall the lugnuts. I remember
> thinking "man, these lugnuts are tight" when I took them off.

Umm - you used an impact wrench to tighten them, and then you had the
pulsating? Your problem was *not* that they weren't tight enough - they
were probably *too* tight (as further evidenced by your having to use a
breaker bar to get them off the next time).

(Your post is a little confusing - if you're saying that the first time
you took them off, they were extremely tight, then whoever had put your
wheels on the previous time had overtightened them - probably with an
impact - if it was a shop that did that, find another shop to work on
your car.)

> I had to
> use a breaker bar to get them loose. I torque things like head bolts,
> but have never bothered to torque lug nuts.
>
> Soon after, my brake pedal started pulsating. Same rotors, same brake
> pads. So I'm convinced the pro who explained the cause to me was
> correct. There's a reason why that torque spec is so high.

I'm confused. The pro (golfer? wrestler?) told you they were too loose,
yet you had tightened them with an impact wrench, after which you had
pulsation, and had to use a breaker bar to get them off?

> ...torque the lug nuts to spec. It's the right thing to
> do...

I'll go along with that.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')