Accord 2000 - Question on Brakes wear

I have a 2000-Accord-4DR-EX with ~60,000 miles. I have never changed my
brakes - since new. Today, I went for my annual inspection and the
mechanic said that my front brakes look like new and the rear are
almost gone, but OK until replacement soon.

(1) Should I have both the front and rear replaced at the same time?
Should I replace the rotors at the same time or not.

(2) Are rear ones the first to go, in general?

Thanks in advance
Shanks

 

don't change both at same time unless they need changing. You
obviously have disc brakes on the rear - they IMHO are too small and
wear out fast - have my origional shoes on drum brakes at 189K miles -
got about 113 on first set of pads and 70K on cheap autozone pads.

Have always wondered why auto makers put such small pads on the rear.

Also whatever you do do not let the repair guys talk you into turning
your rotors - big mistake - every time they turn they get thinner and
more of a chance of warping. Also tell them to use torque wrenches not
torque sticks and never ever impact wrenches - will bend/warp your
rotors.

 

Two reasons:
1) To give them a chance of getting even remotely warm in use
2) To make the parking brake bite properly with reasonable effort.

 

No. Not if the fronts look brand new. Rears-only are fine.

BUT: Have the fronts checked to make sure the pins and pads are floating
freely with no binding at all.

Not if they're not warped or badly scored.

Turning *can* increase the probability of future warping because it reduces
heat-sink mass if taken too deep. A light skim is no problem, though.

Yes, on a car with rear discs where the parking brake uses the disc pads.

 

TeGGeR® wrote:

Why is that?

Without knowing any better I would think that using the rear disks as
the parking brake would not put any additional wear on the pads because
it's not engaged until the car is stopped, i.e., the disks aren't
turning with the parking brake on, therefore no wear on the pads.

 

as a side note- my local dealer, norm reeves honda of cerritos, CA sent
me a flyer with their service specials in it. they want $165 to do the
front brakes... damn. $165, and thats a "special"?

and that doesnt include turning the rotors, which would be extra, if
needed. but it does include a complete inspection of the brake system!
something i can do in 10 minutes myself.

id change front pads all day for $165 a pop. hell, id even drive to
someones home or place of business and do it there!

 

Why would small pads enable the p-brake to bite any better than large pads?

 

TeGGeR® wrote

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.
The parking brake has little to do with rear pad wear, unless the car is
driven with the parking brake left on.


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Small pads concentrate the load over a smaller area, resulting in better
"bite" with a lever that's reasonably easy to pull up.

If the pads were bigger, the force exerted by the parking brake lever would
have to be proportionally greater.

 

My friends with cars having pads front and back seem to always wear out
their rear pads first - thus my question as to why the rear pads are so
small. A design screw up in my opinion. With 189K on my rear shoes
and still a lot of miles left on these shoes - shoes it is for me in
the rear - if I have a choice.

 

See my response to Abeness.

It has to do with the size and softness of the pads, and with the leverage
necessary to apply the parking brake.

 

No, has to do with ease of application of the parking brake, and heating up
of the pads in use.

If the pads were larger or harder, either the lever on top of the caliper
(or the parking brake lever) would have to be longer to exert more force,
or you'd have to haul up a lot harder on the lever to set the brake on
hills.

This is Honda's compromise. Our old Toyota MR2 was the same way.

 

TeGGeR® wrote:

true. interestingly, not all cars with rear disks use them as parking
brakes. the subaru legacy has a drum/disk combo. drum is inside &
operated by the hand lever, disk on the outside of the same piece of
cast iron, used for a disk. very good idea as there's always a
completely independant [cool] emergency brake.

 

This doesn't make sense to me: the surfaces are not deforming--at least
the rotor shouldn't be or you get a warped rotor, and that pad material
is pretty tough. Friction between these two surfaces is therefore
essentially independent of contact area (counterintuitive, for sure), so
a larger pad wouldn't provide more friction, but whether large or small,
the p-brake lever applies the same amount of force between the pad and
rotor, and therefore the same amount of contact friction. No more force
is required to press a larger pad against the rotor than a smaller pad.

 

As I reread this I can't quite believe that a larger pad would not
provide more friction--unless the point is to distribute the load over a
larger surface area so that wear is also distributed, and the pads
thereby last longer. Perhaps I'm missing something basic? My physics is
admittedly somewhat rusty.

 

I had the experience of too big rear brakes on an 87 Ford Aerostar. This is
totally apples to oranges in that the Ford was rear drive and had drums on
the rear, but I think it is pertinent to the discussion. When the car was
new, anything beyond light braking caused the rear to lock up. Forget about
driving it when there was rain or God forbid, snow.

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.

My Hondas that have the little parking brake drum inside the rear disk (a
'96 Odyssey and a '00 TL) have the expected longevity on the rear brakes
(they last about 2 years longer than the fronts).

My one Honda that used the rear disks for the parking brake (a '95 Integra)
ate rears about twice as often as the fronts. My suspicion is that the
ratcheting piston doesn't retract as much as they do on normal disk brakes,
causing more drag on the rear brakes. Interestingly, the Nissans in the
immediate family (a '96 and '97 I30 and a 98 Maxima) that use the rear disks
for double duty do not eat rear pads like the Hondas do. The '98 Maxima is
driven by the same driver as the Integra.

 

I don't understand the physics either, and there may be other factors at
work than just the raw physics. All I know is that this is what happens.

The explanation I gave is one I read somewhere, but can't remember what
publication it was in. Road & Track, maybe?

 

and this was still not a proper fix. ford /always/ knew the issue - but
they took the decision to save $'s by /not/ fitting a proportioning
valve. cutting corners is always ford policy - even at the expense of,
well, shall we just mention the word "explorer"?

 

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.

 

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?

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.