outside brake pad more worn?

"Tegger" > wrote in message
...

On every single-piston caliper I remember, if the piston
(on the inside) doesn't move, neither does anything else
and that caliper provides no braking effort.

On 4/1/2011 2:01 PM, Tegger wrote:
> > wrote in
> :
>
>>
>> > wrote in message
>> ...
>>> > wrote in
>>> news >>>
>>>
>>>>
>>>> And then service the pads.
>>>>
>>>>
>>>>
>>>
>>>
>>> The inner pad is his problem, not the caliper.
>>>
>>> --
>>> Tegger
>>
>> Think about what you have said, and I will not flame you so badly. ;>)
>>
>
>
> I think I'm getting flamed anyway. I just washed my brain and I think it
> shrank a bit. "My bad", as they say.
>
> What I failed to think of in my reply--after almost 30-years of working on
> brakes--is that, if the sliders seize, the outer pad will fail to kick away
> from the rotor, and will suffer not only excessive wear, but overheating
> and sometimes a burnt odor. In my reply, I was assuming the inner pad was
> seized and contributing nothing to braking effort, which I have seen
> numerous times on various cars, but none of them J-bodied GMs.
>
> If the inner pad were stuck as I originally suspected, the inner rotor
> surface would have rust on it, since the inner pad would never sweep that
> rust away.

You might want to re-think that one again. If the brake is a floating
caliper design with the piston on the inside, no pressure on the inner
face of the rotor means there's no braking at all.

>
> What the OP needs to do is pull his brakes apart and examine every part of
> them: if the pins are sticking; if the pads are sticking; if the piston
> does not push back in easily.
>
> If you decide to flame me, use a votive candle or something small like
> that.
>

"That Tune" > wrote in news:in5sml$i0$1
@speranza.aioe.org:

> "Tegger" > wrote in message
> ...
>
> On every single-piston caliper I remember, if the piston
> (on the inside) doesn't move, neither does anything else
> and that caliper provides no braking effort.
>
>
>


That's a different kind of problem from what the OP reported. And,
generally speaking, calipers do not fail in this manner.

Pedal-pressure creates immense forces that will overcome any resistance to
outward piston movement, but RETURN forces are tiny by comparison. Rusty
pistons typically allow normal braking effort, but will not let go
afterwards.

--
Tegger

dsi1 > wrote in
:


>>
>> If the inner pad were stuck as I originally suspected, the inner
>> rotor surface would have rust on it, since the inner pad would never
>> sweep that rust away.
>
> You might want to re-think that one again. If the brake is a floating
> caliper design with the piston on the inside, no pressure on the inner
> face of the rotor means there's no braking at all.
>


That would only happen if BOTH the inner pad were totally stuck AND the
caliper sliders were totally stuck; a rather unlikely occurrence.


--
Tegger

On 04/01/2011 11:00 AM, ben91932 wrote:
> On Mar 31, 3:26�pm, > wrote:
>> ('04 Cavalier, but I think I've seen this in other Cavs over the years.)
>>
>> This car has single-piston disk brakes in the front. �The piston pushes
>> on the inside pad. �But, the outside pad had much more wear. �For the
>> outside pad to operate, AIUI, the piston pushes the inside pad against
>> the rotor, and the reaction pushes the piston& caliper inward,
>> resulting in the outer pad pushing against the other side of the rotor.
>>
>> So, how can the outer pad wear, without corresponding wear on the inside
>> pad?
>
> Be safe and thorough with your brakes...
> Reman calipers are cheap.
> Replace them both.
> HTH,
> Ben

in theory, that's true. but dude, some of the remans are complete
garbage.

i've just taken apart a pair of cordone's that were starting to stick.
the previous owner had them installed about a year ago. and those
things are hideous. they were acid etched to clean, but left in the
solution so long, the tolerances are shot to heck. and the main upper
slider pin [honda] is not only loose it's so eroded by the acid, it's
rougher than guts so any sliding is notchy. and the end seal's one-way
air/grease valve has been capped!

terrible terrible rebuild.

so returning to your point, yes, /good/ rebuilds are worth using as
replacements, and yes, the o.p. needs to be safe and thorough on any
work, but i think cheap remans are a liability. i'd never use them on
any vehicle i owned - i'll always service and recondition the originals.


--
nomina rutrum rutrum

On 04/01/2011 06:59 PM, Tegger wrote:
> "That > wrote in news:in5sml$i0$1
> @speranza.aioe.org:
>
>> > wrote in message
>> ...
>>
>> On every single-piston caliper I remember, if the piston
>> (on the inside) doesn't move, neither does anything else
>> and that caliper provides no braking effort.
>>
>>
>>
>
>
> That's a different kind of problem from what the OP reported. And,
> generally speaking, calipers do not fail in this manner.
>
> Pedal-pressure creates immense forces that will overcome any resistance to
> outward piston movement, but RETURN forces are tiny by comparison. Rusty
> pistons typically allow normal braking effort, but will not let go
> afterwards.

and when that "not let go" happens with the sliders, it causes precisely
the situation the o.p. described.


--
nomina rutrum rutrum

On 4/1/2011 4:02 PM, Tegger wrote:
> > wrote in
> :
>
>
>>>
>>> If the inner pad were stuck as I originally suspected, the inner
>>> rotor surface would have rust on it, since the inner pad would never
>>> sweep that rust away.
>>
>> You might want to re-think that one again. If the brake is a floating
>> caliper design with the piston on the inside, no pressure on the inner
>> face of the rotor means there's no braking at all.
>>
>
>
> That would only happen if BOTH the inner pad were totally stuck AND the
> caliper sliders were totally stuck; a rather unlikely occurrence.

I see your point now. You're talking about the pad being completely
frozen to the adapter, not the piston. I've never seen that but then
again, I've never seen a lot to things. Thanks for the clarification.

On 4/1/2011 2:00 PM, ben91932 wrote:
> On Mar 31, 3:26 pm, > wrote:
>> ('04 Cavalier, but I think I've seen this in other Cavs over the years.)
>>
>> This car has single-piston disk brakes in the front. The piston pushes
>> on the inside pad. But, the outside pad had much more wear. For the
>> outside pad to operate, AIUI, the piston pushes the inside pad against
>> the rotor, and the reaction pushes the piston& caliper inward,
>> resulting in the outer pad pushing against the other side of the rotor.
>>
>> So, how can the outer pad wear, without corresponding wear on the inside
>> pad?
>
> Be safe and thorough with your brakes...
> Reman calipers are cheap.
> Replace them both.
> HTH,
> Ben

Yeah, sure, trust your calipers to some 9 year old Mexican kid

On 04/02/2011 06:14 AM, Steve Austin wrote:
> On 4/1/2011 2:00 PM, ben91932 wrote:
>> On Mar 31, 3:26 pm, > wrote:
>>> ('04 Cavalier, but I think I've seen this in other Cavs over the years.)
>>>
>>> This car has single-piston disk brakes in the front. The piston pushes
>>> on the inside pad. But, the outside pad had much more wear. For the
>>> outside pad to operate, AIUI, the piston pushes the inside pad against
>>> the rotor, and the reaction pushes the piston& caliper inward,
>>> resulting in the outer pad pushing against the other side of the rotor.
>>>
>>> So, how can the outer pad wear, without corresponding wear on the inside
>>> pad?
>>
>> Be safe and thorough with your brakes...
>> Reman calipers are cheap.
>> Replace them both.
>> HTH,
>> Ben
>
> Yeah, sure, trust your calipers to some 9 year old Mexican kid

or you can have your brand new g.m. calipers made by some 9-year old
chinese kid with congenital myopia.

http://en.wikipedia.org/wiki/Myopia#Myopia_in_China



one more caution to add to the low quality rebuild thing - when
rebuilders "clean" calipers in their acid bath, all the original
corrosion-resistant cadmium plating is removed and not replaced. for
the most part, this is more a cosmetic thing than anything else, but
there is one critical area where this becomes vary important - the root
of the "claw" that grips around the disk. if that root gets to corrode
because its protective plating has been removed, the rust pitting can
initiate fatigue, and the claw can break. i really wish i still had a
picture of it, but i did some work on a vehicle failure where one of the
toes on the claw had fatigued and cracked off. fortunately for the
driver in this case, the other toe was still there but nevertheless,
this was a potentially life-threatening safety flaw and one whose onset
could have been prevented by avoiding misguided/low quality rebuild
practices.


--
nomina rutrum rutrum

Steve Austin > wrote in
:

> On 4/1/2011 2:00 PM, ben91932 wrote:
>> On Mar 31, 3:26 pm, > wrote:
>>> ('04 Cavalier, but I think I've seen this in other Cavs over the
>>> years.)
>>>
>>> This car has single-piston disk brakes in the front. The piston
>>> pushes on the inside pad. But, the outside pad had much more wear.
>>> For the outside pad to operate, AIUI, the piston pushes the inside
>>> pad against the rotor, and the reaction pushes the piston& caliper
>>> inward, resulting in the outer pad pushing against the other side of
>>> the rotor.
>>>
>>> So, how can the outer pad wear, without corresponding wear on the
>>> inside pad?
>>
>> Be safe and thorough with your brakes...
>> Reman calipers are cheap.
>> Replace them both.
>> HTH,
>> Ben
>
> Yeah, sure, trust your calipers to some 9 year old Mexican kid



Wanna see aftermnarket rebuilding? Here's a YouTube video of driveshaft
remanufacturing:
<http://www.youtube.com/watch?v=BrAWzmdCXWI&feature=related>

Watch the WHOLE thing, and especially watch what this guy does with the
hammer and griding wheel to these precision-made components!


--
Tegger