Brake puzzle

For what it's worth, here is my experience with a somewhat newer, 98 model.
A great vehicle with just minor problems in ten years of service. I was
never happy with its front brakes, but the pads just refused to wear down,
and would go forever. At around 75,000, with 1/4" thickness still left, I
finally decided that it was time. Installed Raybestos 'Brute Stop' instead
of whatever the original were, and WOW, what a difference -- the thing
actually stops when I want it to! Yes, they wear down fast, and even with my
light foot don't last more than 30,000-40,000, but they are not that
expensive and I can replace them in an hour or so. They also create a lot of
dust, which, if you are very concerned about the looks of your ride, you'd
need to clean from your beautiful magnesium rims at least once a week. They
may even wear the rotors somewhat faster. Yet having to choose between
longevity, esthetics and stopping on a dime in an emergency, I know what I'd
take. Newer types of friction material, like ceramic may deliver the best of
both worlds - no experience with those.

Thanks for that.

I must say that my truck stops pretty well with the factory pads. Though
given your wear experience, sit seems to make sense that you're getting a
stronger response. I drive in such a way that I avoid hard stops. But then
I have to put up with the nuns who give me the finger as they go by because
I'm going so slowly :O)

Seriously, I go the speed limit plus five, almost always using cruise
control. And I assume that if they can go through the red light or cut or
run in front of me, they will. And I leave lots of space between me and the
guy ahead, especially if someone gets up close behind me. I figure if I have
to use my brakes, I didn't anticipate correctly.If I'm heading around a
curve that has a traffic light (as we have on the Saw Mill Parkway in NY), I
let cars get ahead of me, and I use their brake lights to let know whether
the light ahead is red. Save brakes incredibly. I even stay off the brakes
in stop and go traffic!

Anthony Giorgianni
For everyone's benefit, please post back to the group

----- Original Message -----
From: "Happy Traveler" >
Newsgroups: rec.autos.makers.ford.explorer
Sent: Wednesday, April 30, 2008 4:44 PM
Subject: Brake puzzle


> For what it's worth, here is my experience with a somewhat newer, 98
> model. A great vehicle with just minor problems in ten years of service. I
> was never happy with its front brakes, but the pads just refused to wear
> down, and would go forever. At around 75,000, with 1/4" thickness still
> left, I finally decided that it was time. Installed Raybestos 'Brute Stop'
> instead of whatever the original were, and WOW, what a difference -- the
> thing actually stops when I want it to! Yes, they wear down fast, and even
> with my light foot don't last more than 30,000-40,000, but they are not
> that expensive and I can replace them in an hour or so. They also create a
> lot of dust, which, if you are very concerned about the looks of your
> ride, you'd need to clean from your beautiful magnesium rims at least once
> a week. They may even wear the rotors somewhat faster. Yet having to
> choose between longevity, esthetics and stopping on a dime in an
> emergency, I know what I'd take. Newer types of friction material, like
> ceramic may deliver the best of both worlds - no experience with those.
>
>

"Happy Traveler" > wrote in message
news
> For what it's worth, here is my experience with a somewhat newer, 98
> model. A great vehicle with just minor problems in ten years of service. I
> was never happy with its front brakes, but the pads just refused to wear
> down, and would go forever. At around 75,000, with 1/4" thickness still
> left, I finally decided that it was time. Installed Raybestos 'Brute Stop'
> instead of whatever the original were, and WOW, what a difference -- the
> thing actually stops when I want it to! Yes, they wear down fast, and even
> with my light foot don't last more than 30,000-40,000, but they are not
> that expensive and I can replace them in an hour or so. They also create a
> lot of dust, which, if you are very concerned about the looks of your
> ride, you'd need to clean from your beautiful magnesium rims at least once
> a week. They may even wear the rotors somewhat faster. Yet having to
> choose between longevity, esthetics and stopping on a dime in an
> emergency, I know what I'd take. Newer types of friction material, like
> ceramic may deliver the best of both worlds - no experience with those.
>
>

"Ashton Crusher" > wrote in message
news
>
> Is that how it works these days. In the old days they used a hold off
> valve to make sure the rear brakes came on before the fronts because
> it makes the car more stable to do it that way.
>

Your "hold off" valve was actually called a metering valve. This was
required on vehicles with a combination of front disc/rear drum brakes. This
was to keep the front brakes from applying before the rears.... This was
accompl;ished by "metering" the amount of fluid sent to the front brakes -
limiting it, if you will, the movement of the front calipers until the rear
drums "caught up". What it never did was to cause the rear brakes to apply
"first", rather, it's purpose was to have the brakes apply in unison. Which
brings us to the proportioning valve....

The proprotioning valve was there to limit the pressure to the rear brakes.
The harder we brake, the more weight is shifted to the front wheels... If we
allow the rear brakes to lock up early, the car will swap ends...

Notice we haven't mentioned the residual pressure valve.

Some vehicles used a "combination valve". This was a metering valve plus
proportioning valve combined into one unit. But the theory is still the same
and it does not involve applying any one axles brakes "first". Something
like that is going to be a nightmare from a stability standpoint.

With the advent of 4WABs, all of these functions can be incorporated into
the hydraulic control unit.

Misunderstanding both vehicle systems as well as vehicle dynamics can lead
to all kinds of problems... Things "these days" work the same as they did
"in the old days" as far as dynamics are concerned... Depending on the
system, technology may achieve these conditions in a mechanically different
way...

That's fascinating, Jim. Thanks for that.

Anthony Giorgianni
For everyone's benefit, please post back to the group



"Jim Warman" > wrote in message
news:WM7Vj.1744$KB3.869@edtnps91...
> Your "hold off" valve was actually called a metering valve. This was
> required on vehicles with a combination of front disc/rear drum brakes.
> This was to keep the front brakes from applying before the rears.... This
> was accompl;ished by "metering" the amount of fluid sent to the front
> brakes - limiting it, if you will, the movement of the front calipers
> until the rear drums "caught up". What it never did was to cause the rear
> brakes to apply "first", rather, it's purpose was to have the brakes apply
> in unison. Which brings us to the proportioning valve....
>
> The proprotioning valve was there to limit the pressure to the rear
> brakes. The harder we brake, the more weight is shifted to the front
> wheels... If we allow the rear brakes to lock up early, the car will swap
> ends...
>
> Notice we haven't mentioned the residual pressure valve.
>
> Some vehicles used a "combination valve". This was a metering valve plus
> proportioning valve combined into one unit. But the theory is still the
> same and it does not involve applying any one axles brakes "first".
> Something like that is going to be a nightmare from a stability
> standpoint.
>
> With the advent of 4WABs, all of these functions can be incorporated into
> the hydraulic control unit.
>
> Misunderstanding both vehicle systems as well as vehicle dynamics can lead
> to all kinds of problems... Things "these days" work the same as they did
> "in the old days" as far as dynamics are concerned... Depending on the
> system, technology may achieve these conditions in a mechanically
> different way...
>