E28 M535i - cross drilling rotors

> My mechanic says the first thing to try is just cross-drill the existing
> rotors and use a slightly firmer pad. He reckons that will more than be
> good enough for the car given that the engine is stock.

Waste of time and a bit dangerous.

I have Zimmermann cross drilled discs on my E30. I'm hard on the brakes
as I drive the car on quite twisty roads. Cross drilling aids cooling
and if you soak the rotors in standing water it helps clear them (so I'm
told). But there is less surface area so it actually harms stopping
power!

The Zimmermanns have the holes cast in at manufacture. Drilling holes
afterwards can weaken the disc.

--
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I agree with John, its dangerous to try and drill out your rotors,
they're already thin enough. Remember, *true* and *proper*
cross-drilled are cast into the rotor. Drilling only creates stress
risers and will weaken the disc.

If you want the proper "factory" upgrade, and don't want to spend the
big bucks for a Movit or Brembo kit, get yourself a set of E32 750
calipers and rotors up front; E34 540i calipers and rotors in the rear.
You should be able to find the calipers cheap at any junkyard.

The beauty of this setup is your consumables - rotors and pads, are
basically standard BMW stuff that can be bought OE from any dealership
or OEM through any parts store, e.g., BMA parts as great prices.
Further, the bigger brakes are vented for more cooling.

Note - you may need to upgrade to 16" wheels, but since your car came
with those obsolete metric TRX tires and wheels, you'll probably need
to replace them anyways, if you haven't already done so. Good Luck!

DRP535 wrote:
> I've had some mods done recently with the suspension and the car handles a
> lot better now such that I tend to drive it a bit faster and now I'm
> starting to find the limits of the braking capacity. Not that the standard
> brakes are bad by any stretch of the imagination, they're not, but they do
> fade very badly after 2 or 3 really hard stops and the recovery is a slow
> one.
>
> My mechanic says the first thing to try is just cross-drill the existing
> rotors and use a slightly firmer pad. He reckons that will more than be
> good enough for the car given that the engine is stock.
>
> I'm more than willing to give it a try because it's a very cheap mod and
> easy to do but am sceptical than just drilling some holes in the rotors is
> gonna make any difference whatsoever.
>
> Anyone tried it and care to comment?


Sure, I'll comment. Get another mechanic. Your current one is an
imbecile.

Nobody (with any degree of intelligence) cross drills their own rotors.

-Fred W

In article >,
DRP535 > wrote:
> My mechanic says the first thing to try is just cross-drill the existing
> rotors and use a slightly firmer pad. He reckons that will more than be
> good enough for the car given that the engine is stock.

Change your mechanic now. He's a wally.

--
*Why do they put Braille on the drive-through bank machines?

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

DRP535 wrote:

> <chop>
>
>Only remaining issue is the braking endurance. There's nothing wrong with
>the braking as such. The car pulls up dead straight, doesn't wander around
>on the road and everything feels rock solid, but you can only do it once
>from high speed before there's no pedal left afterwards.
>
>

So....this thread is getting long, but I don't recall that you changed
pads. It seems quite possible that a higher (and wider!) temperature
range pad could resolve your problems at lower cost...

JRE

"DRP535" > wrote
> I've had some mods done recently with the suspension and the car handles a
> lot better now such that I tend to drive it a bit faster and now I'm
> starting to find the limits of the braking capacity. Not that the standard
> brakes are bad by any stretch of the imagination, they're not, but they do
> fade very badly after 2 or 3 really hard stops and the recovery is a slow
> one.

Make sure that the air ducts that direct air to the rotors are open (in the
grill) and actually have ductwork. IIRC, some cars had it left off...

Floyd

<If I was to do this mod, would the standard issue spare wheel fit over

either of the E32 or E34 brake calipers? >

E28 and E34 have the same front brakes fitment, go here for "upgrade"
possibilities:


http://www.bmwe34.net/e34main/upgrade/brakes.htm

You may be satisfied just by changing to different pads. I use Carbotech
pads on the track in my E34 M5, and don't experience any fade. I don't
use drilled rotors.
When did you last change the brake fluid?

Here is a link:
http://www.carbotecheng.com/main.htm

Mark

--
http://www.dsylva-tech.ca
OBD-1 and OBD-II Performance software for BMW's


"DRP535" > wrote in message
...
> I've had some mods done recently with the suspension and the car handles a
> lot better now such that I tend to drive it a bit faster and now I'm
> starting to find the limits of the braking capacity. Not that the standard
> brakes are bad by any stretch of the imagination, they're not, but they do
> fade very badly after 2 or 3 really hard stops and the recovery is a slow
> one.
>
> My mechanic says the first thing to try is just cross-drill the existing
> rotors and use a slightly firmer pad. He reckons that will more than be
> good enough for the car given that the engine is stock.
>
> I'm more than willing to give it a try because it's a very cheap mod and
> easy to do but am sceptical than just drilling some holes in the rotors is
> gonna make any difference whatsoever.
>
> Anyone tried it and care to comment?