Greetings:
Any comments on the replacing-vs-turning of the front brake rotors on
a 2001 525i?
I'm told by BMW techs that they MUST be replaced at each brake job.
I'm also told by a brake shop owner who works on BMWs among others
that it's not always necessary. I need them done but don't want to
give BMW any more money than I already have for things which may or
may not need doing.
Thanks in advance.

In article
<042e5179-388a-4ed6-ba48-89d30cb41f7d (AT) m3g2000pri (DOT) googlegroups.com>,
HDGoose <IlDonPeppino (AT) yahoo (DOT) com> wrote:
BMW discs have the minimum thickness stamped on the hub so can be easily
measured for wear.

It's not worth having them skimmed as any grooves deep enough to need
this will go down below the minimum thickness.

I find discs last for two sets of pads.

If you really want to save money fit OEM parts yourself. It's an easy job.
Took me a morning to change all four discs and their pads and saved 500
gbp over dealer prices. Wish I could make over 100 an hour at work. ;-)

--
*The most wasted day of all is one in which we have not laughed.*

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

"HDGoose" <IlDonPeppino (AT) yahoo (DOT) com> wrote
BMW uses very soft pads and rotors, so that stopping is good in all
conditions.
As a result, the pads often last only 15K-20K miles; but usually go 40K-50K.
Also as a result of the soft iron used in the rotors, they never last more
than
two sets of pads before reaching minimum thickness. Often, they will last
only one set of pads before their lifetime is used up. Remember, if you use
more than 50% of the available rotors' thickness with the first set of pads,
you're going to be under specification at some time during the 2nd pad's
lifetime, whereupon you will need to change both the pads and rotors in
any case.

Since the rotors are cheap (Bav Auto shows them at $55 each, with OEM
Mintex pads at $45) you should probably just replace the rotors.

The dealers are a rip-off. Go somewhere else. Or, buy the parts and
do it yourself, or buy the parts and take them to a corner shop. They're
dead easy to install (except for the sensor, which requires an easy touch
not a big hammer - not the strong point of many garages.)

The rears usually last twice as long as the front, btw. Do not change
all 4 corners unless the rears are actually gone.

FloydR

"Floyd Rogers" <fbloogyuds (AT) hotmail (DOT) com> wrote
Forgot to address re-finishing. Re-finishing removes thickness. On BMW
rotors, it's very likely to result in the rotor going under-spec during the
2nd
pad's lifetime, and is therefore not recommended. Occasionally, it is
necessary
to cure a wobble if the rotor warps a little. Usually re-finishing in those
cases fixes it for a while, but it will eventually un-warp or warp worse and
you'll have to replace it anyway.

FloydR

On Oct 27, 1:13*pm, "Dave Plowman (News)" <d... (AT) davenoise (DOT) co.uk>
wrote:
I agree with Dave.
For most german cars, it's NOT good to cut the rotors.
if rotors are bad replace, DO NOT CUT.

Good luck,
Oskar

On Oct 27, 10:54*am, HDGoose <IlDonPepp... (AT) yahoo (DOT) com> wrote:
Thanks for all that good info. I would have considered doing them
myself, or at least have my local shade tree mechanic do it, but
"they" make it sound like because of the ABS it's a technical job
requiring a special touch and unobtanium tools. So basically, with the
exception of the sensor, I (or more likely my shade tree guy) can just
swap out the rotors and pads like a "regular" car?

"HDGoose" <IlDonPeppino (AT) yahoo (DOT) com> wrote
Absolutely.
The sensor is easy, but just a little fiddling. It fits into the center of
the inner pad: it should just slide in. You can re-use the old ones
if you want to save $10-$15, but they often don't come out clean
or slide in as well as new ones. Also, don't force the electrical
connector; you can break the retention tabs or pins.

FloydR

In article
<a1fb5d81-6345-4500-9322-209b4a6097e1 (AT) m3g2000pri (DOT) googlegroups.com>,
HDGoose <IlDonPeppino (AT) yahoo (DOT) com> wrote:
Perhaps to your local 'experts' metric hex keys do represent unobtainable
tools. I'd try and find some honest experts.

--
*Learn from your parents' mistakes - use birth control.

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

Dave Plowman (News) <dave (AT) davenoise (DOT) co.uk> wrote:
There are some fancy tools required if you are going to take the brake
calipers apart, but you aren't going to do that so don't worry.

The BMW brakes are fairly easy, BUT I will say that the BMW rotors are
generally more difficult than most to turn down properly. So I'd suggest
just replacing the rotors if the runout is too high on them rather than
trying to turn them down.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article <hc85de$gdp$1 (AT) panix2 (DOT) panix.com>,
Scott Dorsey <kludge (AT) panix (DOT) com> wrote:
Last time I overhauled a BMW caliper I managed without any special tools.
Which ones were you referring to?

In general if they need 'turning' there won't be enough meat left to do
this. They have to remain above the minimum thickness for the life of the
pads. Although My guess is that minimum is pretty generous.

--
*If I worked as much as others, I would do as little as they *

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.