OT - Can You Bed Brakes Twice?

[DerbyDad03]

Hypothetical situation:

Let's say you follow the bedding procedure recommended for the pads and rotors that you just
installed. Soon afterwards you have a need to take the wheels off, do some more work and then
clean the rotors with brake cleaner again. I assume that the brake cleaner will remove any pad
material that was transferred during the bedding process.

What happens when you go through the bedding process again? Have the pads changed in such a
way that they will no longer transfer material like they did the first time? Is it worth the trouble to bed
them again?

Just curious...

[Gordon Shumway]

Here is an excellent how to for bedding brakes and an answer to your
question.

http://www.zeckhausen.com/bedding_in_brakes.htm

[Oren]

On Fri, 27 Nov 2015 13:31:23 -0800 (PST), DerbyDad03
<teama...@eznet.net> wrote:

Derby, I not familiar with what you call "bedding". I presume you
mean cleaning dirt, and grime from pads and discs. Sandpaper cleans
them.

[DerbyDad03]

Nothing personal, but I'm not sure that that is an "excellent how to".

As far as I know, there is no one size fits all bedding procedure.
Different manufacturers have their own procedure that they want you
to follow. I've installed 2 different brands of rotors and pads recently
and they both had different bedding procedures.

Some examples can be found here:

http://www.tirerack.com/brakes/tech/techpage.jsp?techid=85

stoptech.com says this:

"Because the adherent temperature range for brake pads varies widely
(typically 100°F-600°F for street pads and 600°F-1400°F for race pads),
each bed-in needs to be application-specific. One could try to generate
a one-size-fits-all procedure, but too little heat during bed-in keeps
the material from transferring to the rotor face while overheating the
system can generate uneven pad deposits due to the material breaking
down and splotching (that's a technical term) on to the rotor face."

The zeckhausen site does however seem to indicate that going through
the bedding process more than once is a good thing, so thank you for that.

In the case of my hypothetical situation, I would have to assume that if
the rotors were cleaned after the initial bedding, then the brakes should
be bedded in *two* more times to ensure proper transfer.

[DerbyDad03]

No, that is not what bedding brakes is. Bedding brakes in the process of
transferring pad material to the rotors through a series of heating up
and cooling down of the pads and rotors.

Here's a decent white paper on the subject:

http://www.centricparts.com/files/technical%20guides/pad-and-rotor-bed-in.pdf

[trader_4]

On Friday, November 27, 2015 at 5:43:42 PM UTC-5, Oren wrote:

Neither are the vast majority of people who get their brakes
done every day. The shop doesn't give you specific instructions, just
the keys and off you go. And apparently it's not a problem. I've
bought a lot of pads over the years, don't recall any specific
instructions included either. Just normal driving works. I wouldn't
do any extreme stops the first couple hundred miles, but other than
that, I've never followed any procedures. Now if you have a race
car, are doing that kind of aggressive driving, then I can see the need
for a special process. The rest of us, just drive normally.

[Oren]

I never got that fancy. I'd try to prevent "glazing" of the pads.
Turning the drums and rotors and measuring the tolerance so the pad
made the proper contact on all portions of the pads. But that link is
from smarter people than me :)

[Vic Smith]

Never "bedded" brakes. Done many brake jobs over the years, and the
brakes lasted for years each time.
If the rotors are grooved, I replace them too.
This sounds like the agonizing over the "hygroscopic nature" of brake
fluid. I never changed my brake fluid either.

[Oren]

Only thing I did over the years was to remove any grease/oil from
pads caused by dirty hands - sandpaper cleaned it. (I've done dozens
of sets of brakes)

Back in the day, if a clutch was slipping due to heat "glazing" (shiny
material) we used a tree -- in gear, released the clutch and gave it
some gas acceleration. It actually cleaned the clutch pad for a
better grip and no more slippage. Plenty of ways to skin a cat and
have properly working brakes (or a clutch) :)

Out of tolerance drums and rotors are a different concern.

[Oren]

On Fri, 27 Nov 2015 18:52:04 -0600, Vic Smith
<thismaila...@comcast.net> wrote:

>If the rotors are grooved, I replace them too.

The rotors (or drums) are marked with a measurement tolerance. They
can be turned on a lath at the shop and become almost like new.

A good shop will tell you when and if they need replacement.

[Vic Smith]

I never get rotors turned, for a variety of reasons. The primary
reason is a new one costs 20-40 bucks. Chevy.
I do the brakes myself.

[Tony Hwang]

Rotors on new cars are so light, there is nothing to turn.
Just replace them. My brakes last at least 110K mils or so.
Only needs one brake job before I replace the car. If rotor is
over torqued it wraps so easy these days.

[Stormin Mormon]

On 11/27/2015 6:40 PM, Oren wrote:
> I never got that fancy. I'd try to prevent "glazing" of the pads.
> Turning the drums and rotors and measuring the tolerance so the pad
> made the proper contact on all portions of the pads. But that link is
> from smarter people than me :)
>

This is not a web portal or a vehicle forum. This is Usenet,
forum known as alt home repair.

--
.
Christopher A. Young
learn more about Jesus
. www.lds.org
.
.

[rbowman]

On 11/27/2015 05:52 PM, Vic Smith wrote:
> Never "bedded" brakes. Done many brake jobs over the years, and the
> brakes lasted for years each time.

I never knew it was a formal procedure either. I do know when I change
pads on a bike I don't plan on doing any 60 to 0 tests for a few days.

> This sounds like the agonizing over the "hygroscopic nature" of brake
> fluid. I never changed my brake fluid either.

I have one bike that uses DOT 5, the 'hydrophobic' stuff. Other than not
stripping paint it sucks, but I'm too lazy to do all the flushing needed
to go back to DOT 4.

[cl...@snyder.on.ca]

On Fri, 27 Nov 2015 14:53:31 -0800 (PST), DerbyDad03

Just clea ning with brake-Kleen is unlikely to seriously affect the
previous bedding - but don't sand either the pads or the rotors - the
rotors in particular. Redoing the "bedding"won't hurt, in any case -
but should not be necessary

[cl...@snyder.on.ca]

On Fri, 27 Nov 2015 18:52:04 -0600, Vic Smith
<thismaila...@comcast.net> wrote:

And never kept the vuhicle long enough to havr the calipers or cyls
sieze or leak due to corrosion?
It WILL happen eventually if the fluid is not changed.

[cl...@snyder.on.ca]

On Fri, 27 Nov 2015 17:23:27 -0800, Oren <Or...@127.0.0.1> wrote:

At the cost of most rotors, and the labor rate at most shops, it
doesn't make financial sense to turn grooved rotors - particularly
since when turned close to the limit they are more likely to warp
because they can't hold enough heat (btus) without overheating and
can't shed the heat fast enough.

[Vic Smith]

Well, it hasn't happened to me. My current cars are 22 and 13 years
old. Previous cars were a similar age. Hell, it's not even on the
maintenance schedule for my Chevy.

[trader_4]

I've never changed brake fluid either. No unusual component failures here.
In 40 years, had one master cylinder go and that was on a Fiat that was
only a couple years old. Nuff said. At least one caliper would go on that
car almost every winter too. Not because of the fluid, but because Fiats
were crap and couldn't take any road salt. Don't know of any friends or
family that change brake fluid either and no problems there either. IMO
caliper failures are from salt and corrosion, not the fluid. Evidence of
that is that they typically fail after new pads are put on and the outter part
of the piston, which has been out of caliper housing is pitted, corroded etc.
The part inside, behind the seal, in the fluid is fine.

[cl...@snyder.on.ca]

On Sat, 28 Nov 2015 01:46:27 -0600, Vic Smith

<thismaila...@comcast.net> wrote:

>On Fri, 27 Nov 2015 22:52:09 -0500, cl...@snyder.on.ca wrote:
>
>>On Fri, 27 Nov 2015 18:52:04 -0600, Vic Smith
>><thismaila...@comcast.net> wrote:
>
>>>This sounds like the agonizing over the "hygroscopic nature" of brake
>>>fluid. I never changed my brake fluid either.
>
>>And never kept the vuhicle long enough to havr the calipers or cyls
>>sieze or leak due to corrosion?
>>It WILL happen eventually if the fluid is not changed.
>
>Well, it hasn't happened to me. My current cars are 22 and 13 years
>old. Previous cars were a similar age. Hell, it's not even on the
>maintenance schedule for my Chevy.

As a mechanic I can tell you I've done a lot of brake jobs on older
cars where there was significant rust and corrosion in the cyls.

However, that's not the only issue. Water in brake fluid boils at a
lower temoerature than the brake fluid - causing brake fade under hard
braking. - another reason to change fluid every 5 years or so, Newer
vehicles seal the master cyl against air and moisture intrusion a
whole lot better than older ones too - - -

[rbowman]

On 11/28/2015 08:36 AM, cl...@snyder.on.ca wrote:
> As a mechanic I can tell you I've done a lot of brake jobs on older
> cars where there was significant rust and corrosion in the cyls.

I remember honing the cylinders to clean them up. I might even have a
brake cylinder hone around some place next to the dwell meter and timing
light.

I did have to rebuild the front master cylinder on the Harley last year,
but there was no corrosion after 17 years, just tired seals.

[Oren]

On Sat, 28 Nov 2015 13:55:56 -0700, rbowman <bow...@montana.com>
wrote:

>On 11/28/2015 08:36 AM, cl...@snyder.on.ca wrote:
>> As a mechanic I can tell you I've done a lot of brake jobs on older
>> cars where there was significant rust and corrosion in the cyls.
>
>I remember honing the cylinders to clean them up. I might even have a
>brake cylinder hone around some place next to the dwell meter and timing
>light.
>

Pretty sure I have a cylinder hone with worn stones, next to a
tack/dwell meter and timing light. I'll have to remember to put them
in a yard sale this Spring :)

[Stormin Mormon]

On 11/28/2015 3:55 PM, rbowman wrote:
>
> I did have to rebuild the front master cylinder on the Harley last year,
> but there was no corrosion after 17 years, just tired seals.

No longer capable to be circus seals?

[rbowman]

On 11/28/2015 03:44 PM, Stormin Mormon wrote:
> On 11/28/2015 3:55 PM, rbowman wrote:
>>
>> I did have to rebuild the front master cylinder on the Harley last year,
>> but there was no corrosion after 17 years, just tired seals.
>
> No longer capable to be circus seals?
>

Yeah, they wouldn't work for fish anymore. Losing the front brake
reminded me of the bad old days when the Harley front brake was a cable
operated drum brake. You didn't have to worry about hydraulic failure.
Mostly you didn't use it anyway since it had all the stopping power of
dragging your feet.

[Bob F]

Stormin Mormon wrote:
> On 11/27/2015 6:40 PM, Oren wrote:
>> I never got that fancy. I'd try to prevent "glazing" of the pads.
>> Turning the drums and rotors and measuring the tolerance so the pad
>> made the proper contact on all portions of the pads. But that link is
>> from smarter people than me :)
>>
>
> This is not a web portal or a vehicle forum. This is Usenet,
> forum known as alt home repair.

Jeeezzze! One of the worst off-topic posters in the group complains about
someone elso doing the same?????

The post was a LOT closer to topic than most of yours.

Maintain house, maintain car ---- Seems almost on topic.

[Bob F]

Sounds a lot like the process to bed brakes.
Most clutches probably have to wait for a begining drive to get bedded.

[Bob F]

Did you ever adjust the linkage between the 2 shoes? That makes a world of
difference sometimes.

[rbowman]

On 11/28/2015 08:26 PM, Bob F wrote:
> Did you ever adjust the linkage between the 2 shoes? That makes a world of
> difference sometimes.

You mean that pain in the butt star wheel? It's been about 50 years and
I can't remember if a '55 FLH even had one. As far as I can tell from
the parts, no.

http://www.jpcycles.com/product/240-103

A lot of people took the front brake off completely and it wasn't that
much of a loss. That says a lot since on a bike it's the front brake
that's supposed to be doing most of the work.

[Oren]

On Sat, 28 Nov 2015 19:20:35 -0800, "Bob F" <bobn...@gmail.com>
wrote:

>> Back in the day, if a clutch was slipping due to heat "glazing" (shiny
>> material) we used a tree -- in gear, released the clutch and gave it
>> some gas acceleration. It actually cleaned the clutch pad for a
>> better grip and no more slippage. Plenty of ways to skin a cat and
>> have properly working brakes (or a clutch) :)
>>
>
>Sounds a lot like the process to bed brakes.
>Most clutches probably have to wait for a begining drive to get bedded.
>

<https://tinyurl.com/z4f9we9>

The right side of the photo shows "glazing". Using the tree method
helped to clean it off to help stop slipping. At least in practice, it
did help. Postponed the eventual repair.

[Oren]

On Sat, 28 Nov 2015 19:17:47 -0800, "Bob F" <bobn...@gmail.com>
wrote:

Not long ago, the Mormon asked about wiring in his truck.

Somehow he thinks Usenet if a formal forum roundtable. It isn't. "Alt"
groups are anarchist in nature and by design.

He calls Usenet a "list" :)

[Oren]

On Fri, 27 Nov 2015 21:20:55 -0500, Stormin Mormon
<cayo...@hotmail.com> wrote:

>On 11/27/2015 6:40 PM, Oren wrote:
>> I never got that fancy. I'd try to prevent "glazing" of the pads.
>> Turning the drums and rotors and measuring the tolerance so the pad
>> made the proper contact on all portions of the pads. But that link is
>> from smarter people than me :)
>>
>
>This is not a web portal or a vehicle forum. This is Usenet,
>forum known as alt home repair.

It isn't a "list" and it isn't a "forum".

You seemed pleased to ask about wiring in your truck, recently.

You spent years not conforming with Usenet RFC's by top posting and
flooding the group with a non-delimited sig file over four lines so
people would know you are a Mormon. So what? We know you're a
Mormon.

[Bob F]

I wouldn't be surprised if it was really the bedding of the facing metal that
was improving the performance. It seems to me that that gives you the same
material contacting on both surfaces, which does in many cases increase friction
if I remember my physics classes correctly.

[Bob F]

I wasn't happy with the front drum brake performance on my '69 Honda CB350. By
adjusting the linkage between the two shoes, I could get it so I could lock the
wheel with 2 fingers. Never owned another bike, but I put 60,000 miles on that
one.