Disc Brakes
 

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?

Disc Brakes
 

"DerbyBorn" wrote in message
2.222...

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?

so mercedes etc can sell you discs ......

Disc Brakes
 

On Sat, 06 May 2017 17:41:55 +0000, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't allow
a lip to develop on the periphery of the disc?


****wit.

When the pads wear enough, the lips will meet and prevent the pad from
contacting the disc.

Disc Brakes
 

On 06/05/2017 18:41, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?



The lip is the indication that the disks need replacing. If the pads
were larger you wouldn't get an easily seen indication of the thinness
of the disks.

--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

Disc Brakes
 

On 06/05/17 18:41, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?

cos then they'd put a lip on the pads instead


--
All political activity makes complete sense once the proposition that
all government is basically a self-legalising protection racket, is
fully understood.

Disc Brakes
 

On 06/05/17 18:57, Walter wrote:
On Sat, 06 May 2017 17:41:55 +0000, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't allow
a lip to develop on the periphery of the disc?


****wit.

When the pads wear enough, the lips will meet and prevent the pad from
contacting the disc.

****wit. The pads would be down to metal before they met


--
No Apple devices were knowingly used in the preparation of this post.

Disc Brakes
 

On 5/6/2017 7:13 PM, alan_m wrote:
On 06/05/2017 18:41, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?



The lip is the indication that the disks need replacing. If the pads
were larger you wouldn't get an easily seen indication of the thinness
of the disks.

The right answer, IMHO

Disc Brakes
 

The Natural Philosopher wrote:

On 06/05/17 18:41, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?

cos then they'd put a lip on the pads instead

I am sure you are right. Secondly it would produce an axial force on
the pad, thirdly it would render part of the pad unused. Fourthly, and
I think most importantly, movements of the pad against the edge of the
disc would shatter the outer few millimeters of the pad material (which
has little tensile strength) so you would be back to the bearing surface
of the pad being inside the perimeter of the disc quite quickly.

--

Roger Hayter

Disc Brakes
 

Disc Brakes
 

On 06/05/2017 20:30, newshound wrote:
On 5/6/2017 7:13 PM, alan_m wrote:
On 06/05/2017 18:41, DerbyBorn wrote:

Why don't they make the pads just a bit bigger so that they don't
allow a
lip to develop on the periphery of the disc?



The lip is the indication that the disks need replacing. If the pads
were larger you wouldn't get an easily seen indication of the thinness
of the disks.

The right answer, IMHO

Sorry, I don't agree! You often get some rust on the outer bit of the
disk, outside where the pad rubs, making any lip look a lot thicker than
it really is. Besides which, disks are allowed to wear quite a lot
before they need replacing. There's quite a substantial lip on mine, but
the disks are still within spec when measured with a micrometer.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Disc Brakes
 

In article 2,
DerbyBorn wrote:
Why don't they make the pads just a bit bigger so that they don't
allow a lip to develop on the periphery of the disc?

The entire pad needs to be in contact with the disc. If it overlapped it,
the differential in heat would cause it to break up.

--
*Laugh alone and the world thinks you're an idiot.

Dave Plowman London SW
To e-mail, change noise into sound.

Disc Brakes
 

On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me.
A micrometer and the specification is the proper way of establishing wear
surely though.

But unlikely to be the way the MOT tester "advises" a replacement.


--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

Disc Brakes
 

On 07/05/17 03:30, alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me.
A micrometer and the specification is the proper way of establishing wear
surely though.

But unlikely to be the way the MOT tester "advises" a replacement.


Indeed. Unless you do a huge mileage, uneven disc wear and scoring are
likely to be more of a reason to replace that simple disk thickness..


--
The biggest threat to humanity comes from socialism, which has utterly
diverted our attention away from what really matters to our existential
survival, to indulging in navel gazing and faux moral investigations
into what the world ought to be, whilst we fail utterly to deal with
what it actually is.

Disc Brakes
 

I am given to understand its to stop the material breaking up around the
outside because its still thick enough to hold the rest together.

Not that I know a lotabout cars, but that seems to be the reason people are
given.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Jim GM4DHJ ..." wrote in message
...

"DerbyBorn" wrote in message
2.222...

Why don't they make the pads just a bit bigger so that they don't allow a
lip to develop on the periphery of the disc?

so mercedes etc can sell you discs ......

Disc Brakes
 

In article ,
alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me. A micrometer and the specification is the proper
way of establishing wear surely though.

But unlikely to be the way the MOT tester "advises" a replacement.

At least some cars have the minimum thickness stamped on the disc hub.

Generally, discs need replacing every second set of pads.

--
*If you tell the truth, you don't have to remember anything.*

Dave Plowman London SW
To e-mail, change noise into sound.

Disc Brakes
 

Dave Plowman (News) wrote:

In article ,
alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me. A micrometer and the specification is the proper
way of establishing wear surely though.

But unlikely to be the way the MOT tester "advises" a replacement.

At least some cars have the minimum thickness stamped on the disc hub.

Generally, discs need replacing every second set of pads.

This is partly because by the time you have taken them off it costs
relatively little more buy new ones than to skim the old ones.
Probably a lot less if you haven't got your own suitable lathe.

--

Roger Hayter

Disc Brakes
 

In article ,
Roger Hayter wrote:
Dave Plowman (News) wrote:

In article ,
alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me. A micrometer and the specification is the proper
way of establishing wear surely though.

But unlikely to be the way the MOT tester "advises" a replacement.

At least some cars have the minimum thickness stamped on the disc hub.

Generally, discs need replacing every second set of pads.

This is partly because by the time you have taken them off it costs
relatively little more buy new ones than to skim the old ones.
Probably a lot less if you haven't got your own suitable lathe.

Not really - they've worn down below the minimum thickness. Mainly applies
to the vented sort.

Not really understood this US thing of 'turning rotors' Even quite
noticeably grooved ones seem to work ok.

--
*Plagiarism saves time *

Dave Plowman London SW
To e-mail, change noise into sound.

Disc Brakes
 

On 07/05/17 10:53, Roger Hayter wrote:
Dave Plowman (News) wrote:

In article ,
alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me. A micrometer and the specification is the proper
way of establishing wear surely though.

But unlikely to be the way the MOT tester "advises" a replacement.

At least some cars have the minimum thickness stamped on the disc hub.

Generally, discs need replacing every second set of pads.

well that's ******** of course.



This is partly because by the time you have taken them off it costs
relatively little more buy new ones than to skim the old ones.
Probably a lot less if you haven't got your own suitable lathe.

The metal thickness is important - especially in unvented discs, as the
disc is a heatsink that absorbs braking energy.

A skimmed slender disc will get hot quickly and the pads will fade
possibly before a 70mph emergency stop is complete.


--
No Apple devices were knowingly used in the preparation of this post.

Disc Brakes
 

"Brian Gaff" wrote in
:

I am given to understand its to stop the material breaking up around
the outside because its still thick enough to hold the rest together.

Not that I know a lotabout cars, but that seems to be the reason
people are given.
Brian


Mmmm! Hoop Stress.

Disc Brakes
 

Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've been
"lucky" as modern discs and pads are intended to need replacing at the
same time.

Disc Brakes
 

On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've been
"lucky" as modern discs and pads are intended to need replacing at the
same time.

I do my own maintenance and only use a garage for a few things (welding
a sill, replacing a cambelt and replacing a dual-mass flywheel) that
would have cost me more in time off work to do it myself than for them
to do it.

In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

SteveW

Disc Brakes
 

"Steve Walker" wrote in message
...
On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've been
"lucky" as modern discs and pads are intended to need replacing at the
same time.

I do my own maintenance and only use a garage for a few things (welding a
sill, replacing a cambelt and replacing a dual-mass flywheel) that would
have cost me more in time off work to do it myself than for them to do it.

In 30-odd years I have only replaced discs on two cars, both due to slight
warping - I have never worn a disc to the minimum even on cars that have
had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

SteveW

I blame the passing of asbestos for discs wearing out fast .....

Disc Brakes
 

"Jim GM4DHJ ..." wrote in message
...

"Steve Walker" wrote in message
...
On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've been
"lucky" as modern discs and pads are intended to need replacing at the
same time.

I do my own maintenance and only use a garage for a few things (welding a
sill, replacing a cambelt and replacing a dual-mass flywheel) that would
have cost me more in time off work to do it myself than for them to do
it.

In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

SteveW

I blame the passing of asbestos for discs wearing out fast .....

Mine don’t wear out any faster than they did with asbestos was used.

Disc Brakes
 

On 07/05/2017 21:43, Steve Walker wrote:


Are garages pushing unneccessary changes for profit?


Not always. A friend bought a Fiesta, with 41,000 miles showing, from a
main dealer last year. She agreed the price (to include a new MoT),
paid a deposit and arranged to collect it a few days later. Arrived to
find collection delayed an hour because when doing the MoT they decided
the front discs needed replacing - which they did without any question
of additional charge so for a clear loss compared with letting her drive
it away as was.


--
Robin
reply-to address is (intended to be) valid

Disc Brakes
 

Huge wrote:

Steve Walker wrote:

Are garages pushing unneccessary changes for profit?

IMO, yes. AUDI dealers seem very fond of it.

Funny you should say that - although there are other cases where they
say nothing about work being needed.

e.g. I always use an independent MOT tester who does test only, no
repairs, one shock absorber which has been an MOT advisory for "misting"
for the past 4 years, and he thinks it will be a fail next time around,
but the garage has never mentioned it at all, so when I pointed this out
to them, it suddenly became "required" work.

A few days before the cars main warranty ended, the MOT tester pointed
out transmission fluid was leaking from the rear diff, it had just been
serviced by the dealer and they hadn't mentioned it, when I pointed this
out to them, they needed the car back for 3 days while they replaced the
seals and shafts and invoiced £1200 to Audi UK.

Disc Brakes
 

In article ,
Steve Walker wrote:
In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Have you owned a modern car with vented discs?

--
*My luck is so bad that if I bought a cemetery, people would stop dying.

Dave Plowman London SW
To e-mail, change noise into sound.

Disc Brakes
 

"Rod Speed" wrote in message
...


"Jim GM4DHJ ..." wrote in message
...

"Steve Walker" wrote in message
...
On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've
been "lucky" as modern discs and pads are intended to need replacing at
the same time.

I do my own maintenance and only use a garage for a few things (welding
a sill, replacing a cambelt and replacing a dual-mass flywheel) that
would have cost me more in time off work to do it myself than for them
to do it.

In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

SteveW

I blame the passing of asbestos for discs wearing out fast .....

Mine don’t wear out any faster than they did with asbestos was used.
lucky you ...on aveage every second or third set of pads you need discs
these days ....

Disc Brakes
 

"Andy Burns" wrote in message
...
Huge wrote:

Steve Walker wrote:

Are garages pushing unneccessary changes for profit?

IMO, yes. AUDI dealers seem very fond of it.

Funny you should say that - although there are other cases where they say
nothing about work being needed.

e.g. I always use an independent MOT tester who does test only, no
repairs, one shock absorber which has been an MOT advisory for "misting"
for the past 4 years, and he thinks it will be a fail next time around,
but the garage has never mentioned it at all, so when I pointed this out
to them, it suddenly became "required" work.

A few days before the cars main warranty ended, the MOT tester pointed out
transmission fluid was leaking from the rear diff, it had just been
serviced by the dealer and they hadn't mentioned it, when I pointed this
out to them, they needed the car back for 3 days while they replaced the
seals and shafts and invoiced £1200 to Audi UK.

three years ago I took my wagon r for a full price mot to a tyre place and
it passed ...two years ago I got an invitation from them for a £20 mot ...i
took it in and they failed it on pads and discs....cost quoted £150....Got
the wife to do it for £30 parts...took it back and they failed it for poor
efficiency and pulling which was a load of ****e I figured they were in the
huff for not getting the job.....I took it to a full price place without
touching anything ...it passed....if you don't believe me look up mot
history for SDO7 KNN ......ALWAYS pay the full price for an MOT or you WILL
get ripped off .......

Disc Brakes
 

In 30-odd years I have only replaced discs on two cars, both due to
slight warping -

thats funny my '92 mustang passed year after year with an obviously warped
near side front disc .......and my old merc 190e was the same....

Disc Brakes
 

"Jim GM4DHJ ..." wrote in message
...

In 30-odd years I have only replaced discs on two cars, both due to
slight warping -

thats funny my '92 mustang passed year after year with an obviously warped
near side front disc .......and my old merc 190e was the same....

also have you noticed that over the years advisories come and go on
subsequent mots to the same car.....one year it can be front nearside brake
pipe slightly corroded then it disappears ......happens with loads of slight
faults....buggers up your private sale second hand price though...advisories
should be banned .....

Disc Brakes
 

On Monday, 8 May 2017 07:44:27 UTC+1, Jim GM4DHJ ... wrote:

history for SDO7 KNN ......ALWAYS pay the full price for an MOT or you WILL
get ripped off .......

even then you often will. I'm picky about where I take cars for MOTs.


NT

Disc Brakes
 

wrote in message
...
On Monday, 8 May 2017 07:44:27 UTC+1, Jim GM4DHJ ... wrote:

history for SDO7 KNN ......ALWAYS pay the full price for an MOT or you WILL
get ripped off .......

even then you often will. I'm picky about where I take cars for MOTs.


NT

Local Councils often have MOT testing stations for their own vehicles
and apparently by law they're also obliged to offer the service to the public.

Whether they're obliged to publicise the fact or their location is maybe another
matter. The testers themselves seem glad of the work however.

There's a list somewhere on the Moneysavingexpert website

I was charged around £55 for a small van.

Saying that, a lot will probably depend on whether you think the thing is going
to pass first time or not.

michael adams

....

Disc Brakes
 

In article ,
Jethro_uk wrote:
On Sun, 07 May 2017 09:19:31 +0100, The Natural Philosopher wrote:

On 07/05/17 03:30, alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me.
A micrometer and the specification is the proper way of establishing
wear surely though.

But unlikely to be the way the MOT tester "advises" a replacement.


Indeed. Unless you do a huge mileage, uneven disc wear and scoring are
likely to be more of a reason to replace that simple disk thickness..

I used to service a police driving instructors car. His brakes were like
new at 40,000 miles.

Glad I never had to drive behind him in traffic. But then he probably
never did drive in heavy traffic.

I'll bet he was a poor instructor. Given the very short life of brakes on
police cars.

--
*When did my wild oats turn to prunes and all bran?

Dave Plowman London SW
To e-mail, change noise into sound.

Disc Brakes
 

On 08/05/2017 07:31, Jim GM4DHJ ... wrote:
"Rod Speed" wrote in message
...


"Jim GM4DHJ ..." wrote in message
...

"Steve Walker" wrote in message
...
On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've
been "lucky" as modern discs and pads are intended to need replacing at
the same time.

I do my own maintenance and only use a garage for a few things (welding
a sill, replacing a cambelt and replacing a dual-mass flywheel) that
would have cost me more in time off work to do it myself than for them
to do it.

In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

SteveW

I blame the passing of asbestos for discs wearing out fast .....

Mine don’t wear out any faster than they did with asbestos was used.
lucky you ...on aveage every second or third set of pads you need discs
these days ....



My problem has been rust on the surface of the discs leading to
potential MOT failure. It is hard to know just how much rust will be
tolerated. The difficulty I had replacing replacing pads and discs was
getting the piston to retract. I had to buy a special tool on ebay.

--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Disc Brakes
 

"Jim GM4DHJ ..." wrote in message
...

"Rod Speed" wrote in message
...


"Jim GM4DHJ ..." wrote in message
...

"Steve Walker" wrote in message
...
On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've
been "lucky" as modern discs and pads are intended to need replacing
at the same time.

I do my own maintenance and only use a garage for a few things (welding
a sill, replacing a cambelt and replacing a dual-mass flywheel) that
would have cost me more in time off work to do it myself than for them
to do it.

In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

SteveW

I blame the passing of asbestos for discs wearing out fast .....

Mine don’t wear out any faster than they did with asbestos was used.

lucky you ...on aveage every second or third set of pads you need discs
these days ....

I havent needed a set of pads in 10 years and only needed
one set of pads in the previous 45 years with the previous car.

Disc Brakes
 

In article ,
Michael Chare wrote:
My problem has been rust on the surface of the discs leading to
potential MOT failure. It is hard to know just how much rust will be
tolerated. The difficulty I had replacing replacing pads and discs was
getting the piston to retract. I had to buy a special tool on ebay.

Any rust will soon disappear with use. Rust on the disc where the pads
don't touch doesn't matter.

--
*I'm not your type. I'm not inflatable.

Dave Plowman London SW
To e-mail, change noise into sound.

Disc Brakes
 

On Monday, 8 May 2017 10:50:10 UTC+1, Rod Speed wrote:
"Jim GM4DHJ ..." wrote in message
...
"Rod Speed" wrote in message
...

I blame the passing of asbestos for discs wearing out fast .....

Mine dont wear out any faster than they did with asbestos was used.

lucky you ...on aveage every second or third set of pads you need discs
these days ....

I havent needed a set of pads in 10 years and only needed
one set of pads in the previous 45 years with the previous car.

sounds about right for a Crosley.

Disc Brakes
 

On Monday, 8 May 2017 11:04:25 UTC+1, Dave Plowman (News) wrote:
In article ,
Michael Chare wrote:
My problem has been rust on the surface of the discs leading to
potential MOT failure. It is hard to know just how much rust will be
tolerated. The difficulty I had replacing replacing pads and discs was
getting the piston to retract. I had to buy a special tool on ebay.

Any rust will soon disappear with use. Rust on the disc where the pads
don't touch doesn't matter.

+1

Disc Brakes
 

On 07/05/2017 21:43, Steve Walker wrote:
On 07/05/2017 13:41, Andy Burns wrote:
Dave Plowman wrote:

Generally, discs need replacing every second set of pads.

That seems to be the way, though the garage generally tells me I've
been "lucky" as modern discs and pads are intended to need replacing
at the same time.

I do my own maintenance and only use a garage for a few things (welding
a sill, replacing a cambelt and replacing a dual-mass flywheel) that
would have cost me more in time off work to do it myself than for them
to do it.

In 30-odd years I have only replaced discs on two cars, both due to
slight warping - I have never worn a disc to the minimum even on cars
that have had numerous replacements of pads and mileages of 160,000+.

Are garages pushing unneccessary changes for profit?

Some will.
My MOT advisory said pads were close to limit but the service guy said
they were not and didn't need doing.

discs wear more than they did before asbestos was removed from the pads.
The pads are harder and need servos to work these days.

Disc Brakes
 

In article ,
Jethro_uk wrote:
On Mon, 08 May 2017 10:16:38 +0100, Dave Plowman (News) wrote:

In article ,
Jethro_uk wrote:
On Sun, 07 May 2017 09:19:31 +0100, The Natural Philosopher wrote:

On 07/05/17 03:30, alan_m wrote:
On 06/05/2017 22:11, DerbyBorn wrote:

Sounds good to me.
A micrometer and the specification is the proper way of
establishing wear surely though.

But unlikely to be the way the MOT tester "advises" a replacement.


Indeed. Unless you do a huge mileage, uneven disc wear and scoring
are likely to be more of a reason to replace that simple disk
thickness..

I used to service a police driving instructors car. His brakes were
like new at 40,000 miles.

Glad I never had to drive behind him in traffic. But then he probably
never did drive in heavy traffic.

He used gears - "always be in the right gear to accelerate away again"

As the saying goes, a worn gearbox and clutch are much more expensive to
replace than a set of pads. And changing gear purely to slow the car does
cause unnecessary wear on the box and clutch. And uses more fuel and
causes more pollution.


I'll bet he was a poor instructor. Given the very short life of brakes
on police cars.

Operational cars have a different lifestyle.

Yes. They drive under real road conditions.

One of the courses he taught was royal protection - the idea is the
passengers don't know they are in a car - it should accelerate and
decelerate imperceptibly. They used a *very* shallow dish on the bonnet
with a ball bearing in it (and a copper alongside it to pick it up :) )

As I said, glad he doesn't drive in London.

--
*If you can read this, thank a teecher

Dave Plowman London SW
To e-mail, change noise into sound.