Accord 2000 - Question on Brakes wear

TomP > wrote in
:

> TeGGeR® wrote
>:<snip>
>> Yes, on a car with rear discs where the parking brake uses the disc
>> pads.
>
>> Sparky Spartacus wrote:
>>
>> Why is that?
>
> Brake bias, the front brakes are always larger than the rear
> brakes. Why?
> Because more than 70% of braking is done with the front brakes.
> This guy's rear pad wear, compared to the front, is probably due
> to his
> braking habits. I'm guessing this person is an early, easy breaker.
> That is, he applies the brakes with light pressure, and slows
> gradually, way in advance of the final stopping mark. The rear brakes
> are engaged just slightly before the front brakes. So the majority of
> slowing, in this case, is being done with "just" the rear brakes,
> thus the wear.


I brake hard and late. My rears always wear first.

It has nothing to do with the parking brake itself, but the way the rear
brakes have been designed so that the parking brake will operate correctly,
and so the brakes will heat up in use the way they should to burn off
moisture and rust.

It's a compromise that must be made in all FWD cars that have rear discs
which double as a parking brake.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

SadaYama wrote:
>
>>TomP wrote:
>> This guy's rear pad wear, compared to the front, is probably due to his
>>braking habits. I'm guessing this person is an early, easy breaker. That is,
>>he applies the brakes with light pressure, and slows gradually, way in advance
>>of the final stopping mark. The rear brakes are engaged just slightly before
>>the front brakes. So the majority of slowing, in this case, is being done
>>with "just" the rear brakes, thus the wear.
>
>
> TomP, WOW! You just described my braking habits, which is exactly the
> way I brake. Now back to basics. Can someone tell me the right way to
> apply brakes?

I don't think it's wrong to apply brakes as you do--TomP is saying that
it just results in a certain kind of pad wear. Pads aren't expensive,
really, and aren't difficult to replace--and you got 2 years/60,000
miles out of those pads, even with a few times of leaving the p-brake on
while driving, which will burn them up fast. If you're comfortable
braking as you do, i.e., gently, that's just the way you brake. Don't
feel a need to change it.

> This is also very much true! I start driving and suddenly I notice that
> there is a red-light on the indicator panel, which says brake, then I
> realize that the parking brake is still on, and then I disengage it. It
> happened several times. Maybe whenever I park, I should apply parking
> brake hard -- so that my car wouldn't move when I am driving, then I
> remember to release the parking brake, for sure.

Absolutely. The p-brake is there to keep your car from moving while
parked. Engage it fully, with some strength: the service manual says 200
N/20 kg/44 pounds of force. The proper adjustment for my 94 Civic--may
be different for yours--is full engagement within 6-10 clicks, and I'd
have to be completely oblivious to not realize that it's on when it's
fully engaged, not that I've repaired the rear brakes and properly
adjusted the p-brake.

Get in the habit of releasing the p-brake before you put it in gear, and
you won't have a problem.

Abe

Abeness wrote:
> have to be completely oblivious to not realize that it's on when it's
> fully engaged, not that I've repaired the rear brakes and properly
> adjusted the p-brake.

Oops: "NOW that I've repaired..."

Abeness > wrote in :

> E Meyer wrote:
>> The fix Ford eventually came up with was new rear brakes that had
>> about a third LESS friction area. The problem was that the rear
>> brakes were too strong, causing them to lock up as soon as the weight
>> shifted to the front when braking. I think this is why the rears are
>> smaller.
>
> Hunh. That certainly seems to indicate that larger pads = more
> friction, which does seem logical. Sure wish I could get on the phone
> with a Honda engineer for a professional explanation of how this
> works. I guess any physicist would be able to explain it too. I may be
> able to find someone, will post back if I get around to it.



I just had an off-line conversation with somebody who's been following this
thread. He has efectively convinced me that parking brake operation is NOT
there reason for the small pads.

As you suspected, the physics are pretty simple: If you double the pad
area, you halve the force per unit, but then double the units, so the end
result is the same.

However, if the pad area is greater and force per unit is less, the system
has less ability to scrape off surface rust, leading to glaze. Also,
because the brakes can't heat up as much, moisture is less likely to be
dissipated, leading to more rust. And you know how badly rear discs can
rust.

My conclusion from all of this: Rear pads are tiny so they can heat up
properly to dissipate water, and scrape rust off without causing glaze.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

SadaYama wrote:

> > TomP wrote:
> > This guy's rear pad wear, compared to the front, is probably due to his
> > braking habits. I'm guessing this person is an early, easy breaker. That is,
> > he applies the brakes with light pressure, and slows gradually, way in advance
> > of the final stopping mark. The rear brakes are engaged just slightly before
> > the front brakes. So the majority of slowing, in this case, is being done
> > with "just" the rear brakes, thus the wear.
>
> TomP, WOW! You just described my braking habits, which is exactly the
> way I brake. Now back to basics. Can someone tell me the right way to
> apply brakes?
>
> > The parking brake has little to do with rear pad wear, unless the car is
> > driven with the parking brake left on.
>
> This is also very much true! I start driving and suddenly I notice that
> there is a red-light on the indicator panel, which says brake, then I
> realize that the parking brake is still on, and then I disengage it. It
> happened several times. Maybe whenever I park, I should apply parking
> brake hard -- so that my car wouldn't move when I am driving, then I
> remember to release the parking brake, for sure.

There is nothing wrong with your driving/braking habits, and they do not need to
be altered. Just drive and enjoy.

Brake pad "life" expectations, should be considered more by driving conditions,
rather than raw mileage accumulated.


--
Tp,

-------- __o
----- -\<. -------- __o
--- ( )/ ( ) ---- -\<.
-------------------- ( )/ ( )
-----------------------------------------

No Lawsuit Ever Fixed A Moron...

TeGGeR® wrote:
> I just had an off-line conversation with somebody who's been following this
> thread. He has efectively convinced me that parking brake operation is NOT
> there reason for the small pads.
>
> As you suspected, the physics are pretty simple: If you double the pad
> area, you halve the force per unit, but then double the units, so the end
> result is the same.
>
> However, if the pad area is greater and force per unit is less, the system
> has less ability to scrape off surface rust, leading to glaze. Also,
> because the brakes can't heat up as much, moisture is less likely to be
> dissipated, leading to more rust. And you know how badly rear discs can
> rust.
>
> My conclusion from all of this: Rear pads are tiny so they can heat up
> properly to dissipate water, and scrape rust off without causing glaze.
>


Hmmm--ok. Thanks.

>From the shop manual: BRAKES
Front Pad thickness: Standard: 0.41 - 0.45 in Service Limit: 0.06in
Rear Pad thickness: Standard: 0.33 - 0.37 in Service Limit: 0.06in