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Angle grinder, just say no

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Andy Dingley

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Jun 6, 2011, 12:46:06 PM6/6/11
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Bob Minchin

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Jun 6, 2011, 12:58:03 PM6/6/11
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Andy Dingley wrote:
> http://commons.wikimedia.org/wiki/File:Brake_disc_polishing.jpg
>
> 'Merkins, I assume. 8-(
I use a similar method to get the hooked edge off worn discs provided
that there the overall swept area and thickness are within specified limits.

Done carefully with wheels chocked it is perfectly safe.

Bob

Andy Burns

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Jun 6, 2011, 1:01:07 PM6/6/11
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Bob Minchin wrote:

> I use a similar method to get the hooked edge off worn discs provided
> that there the overall swept area and thickness are within specified
> limits.
>
> Done carefully with wheels chocked it is perfectly safe.

And a brick on the accelerator to spin the axle?


Tabby

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Jun 6, 2011, 1:14:14 PM6/6/11
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I dont see a problem, as long you leave the surface flat enough for
the brakes to work correctly.


NT

Jules Richardson

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Jun 6, 2011, 1:36:44 PM6/6/11
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On Mon, 06 Jun 2011 09:46:06 -0700, Andy Dingley wrote:

"Brake disc being polished after damage by worn brake shoes" - except
they'd call them pads in connection with a disc over here, and shoes for
drums. Same with the UK, I'd expect. Oh, hang on, there's a camera
location link - looks like it's in Germany, if that's accurate.

I'm not sure how you can polish a disc with what looks to be a grinding
wheel. I can imagine that you can (safely) remove the lip that forms on
old discs (so long as the disc isn't otherwise too thin) - but I think of
that as disc wear, not damage that occurs due to worn pads (or shoes ;)
Something lost in translation, perhaps.

cheers

Jules

fred

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Jun 6, 2011, 1:46:35 PM6/6/11
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In article
<e081ab72-5a4b-4ac8...@22g2000prx.googlegroups.com>, Andy
Dingley <din...@codesmiths.com> writes

Feck, has anyone _not_ done that :-?
--
fred
FIVE TV's superbright logo - not the DOG's, it's bollocks

MuddyMike

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Jun 6, 2011, 2:01:28 PM6/6/11
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On Jun 6, 6:01 pm, Andy Burns <usenet.aug2...@adslpipe.co.uk> wrote:
> Bob Minchin wrote:
> > Andy Dingley wrote:
> >>http://commons.wikimedia.org/wiki/File:Brake_disc_polishing.jpg
>
> > I use a similar method to get the hooked edge off worn discs provided
> > that there the overall swept area and thickness are within specified
> > limits.
>
> > Done carefully with wheels chocked it is perfectly safe.
>
> And a brick on the accelerator to spin the axle?

Te he, I like that idea. I have taken many a lip off brake disks with an
angle grinder. Sanding the whole surface with a flapper wheel can be good as
well.

Mike


Ron Lowe

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Jun 6, 2011, 2:04:57 PM6/6/11
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AARG.

I just tried that on the Land Rover, with one front wheel jacked up, and
both rear wheels on the ground.

I just drove it off the jack.

( only joking ).
--
R

Onetap

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Jun 6, 2011, 2:19:40 PM6/6/11
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On Jun 6, 5:46 pm, Andy Dingley <ding...@codesmiths.com> wrote:
> http://commons.wikimedia.org/wiki/File:Brake_disc_polishing.jpg
>
> 'Merkins, I assume.  8-(

Wow, are brake discs so expensive? Besides which, I can't see how
you'd get a flat surface. Is there a pic of the cam belt change with a
stanley knife ?

Andy Dingley

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Jun 6, 2011, 2:30:21 PM6/6/11
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On Jun 6, 6:14 pm, Tabby <meow2...@care2.com> wrote:

> I dont see a problem, as long you leave the surface flat enough for
> the brakes to work correctly.

HTF do you do that? If you do this wth an on-car disk lathe, the
clamping needed to ensure that the end result is flat enough is a
significant problem. If you get the slightest run-out, then you have
severe judder when you apply the brakes.

There is no need to "polish" brake disks. Pads do this well enough
(too well in fact) already. The only time you need to machine them is
if they're grooved, and that means removing a significant volume of
metal, across the full width of the disk. I don't believe anyone can
do this with a hand-held angle grinder that won't leave the disks
either dished or with run-out. This also assumes that they're not
worn out for thickness already.

Andy Dingley

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Jun 6, 2011, 2:32:09 PM6/6/11
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On Jun 6, 7:19 pm, Onetap <One...@talk21.com> wrote:
> On Jun 6, 5:46 pm, Andy Dingley <ding...@codesmiths.com> wrote:
>
> >http://commons.wikimedia.org/wiki/File:Brake_disc_polishing.jpg
>
> > 'Merkins, I assume.  8-(
>
> Wow, are brake discs so expensive?

It's an Americanism. They think that disks need to be machined every
pad change.


> Is there a pic of the cam belt change with a stanley knife ?

You don't change cam belts in America. You wait until they break, then
complain about these funny furriners and their "interference engines".
A real V8, like Cusn Bubba's, can of course keep on running with half
the lobes missing off its cam.

abba doodoo

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Jun 6, 2011, 3:53:10 PM6/6/11
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If the pads are being changed then there will be a lip on the disk's
outer edge, particularly now pads are almost as hard as disks.
Removing the lip allows the new pads to bed in properly as there's no
chance of them catching on the lip. Never bothered doing it myself
mind you.

Bob Minchin

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Jun 6, 2011, 5:36:26 PM6/6/11
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Tick over and top gear give a suitable speed for the job and does not
unduly stress the diff as you only need a few minutes per side.

Bob

Dave Liquorice

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Jun 7, 2011, 5:34:03 AM6/7/11
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On Mon, 06 Jun 2011 19:04:57 +0100, Ron Lowe wrote:

>>> Done carefully with wheels chocked it is perfectly safe.
>>
>> And a brick on the accelerator to spin the axle?
>
> AARG.
>
> I just tried that on the Land Rover, with one front wheel jacked up, and
> both rear wheels on the ground.
>
> I just drove it off the jack.

Only with 4WD and the center diff lock engaged. Assuming that there
is a center diff to be locked of course. B-)

--
Cheers
Dave.

The Other Mike

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Jun 7, 2011, 10:12:33 AM6/7/11
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If you align the angle grinder flapper disc correctly the disc will
rotate automatically with the friction from the cutting action so
there is no need for the car to be in gear.

I often do something similar to one of my vehicles that would
otherwise wreck a pair of brand new manufacturer supplied rear discs
in a typical British winter. This enables the discs to last two years
before I have to remove and skim them, at 250 quid a pair I call that
a result.

--

Ron Lowe

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Jun 7, 2011, 2:00:37 PM6/7/11
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Yes, but the modern discos do all the traction control electronically
and automagically. There's no Diff Lock button. I don't know how it's
implimented internally, if the centre diff can be locked by the magic or
not. I believe that it applies braking to the spinning wheel to apply
power to t'others ( like split-pedal brakes ), but I'm really not sure.

I *do* know I'd not put one in 'Drive' with one corner up on a jack just
to find out...

--
Ron

newshound

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Jun 6, 2011, 2:49:50 PM6/6/11
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"Andy Dingley" <din...@codesmiths.com> wrote in message
news:1fb5693f-1116-4320...@h12g2000pro.googlegroups.com...

To be fair, although the photo description says different, the highlight on
the "lip" region is consistent with the guy *just* removing the lip. I'm
with Bob Minchin, taking the lip off is perfectly acceptable as long as the
disks are in spec. And you don't need a brick on the accelerator; idling
speed is fine. I tend to do it with both wheels "off".

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