Slipstream - June 2003

Retread’s Ramblings : Pads & Rotors
by Joe McGlohen
The best combination of pads and rotors that I have found
over ten years of on track research: Un-slotted frozen rotors
in combination with KFP Blue brake pads. These very hard
carbon fiber pads provide excellent life and braking efficiency. The
pads are made with a ceramic insulator to keep the fluid from boiling.
Frozen rotors just last and last and last, and the efficiency is
way up… all other things being equal.
Love Mintex as I do, they fry in severe usage and the good
compounds are not readily off the shelf available from my local
suppliers. And they are just as expensive as any other mentioned
in previous posts here and the KFP pads.
Track Brakes: Expect high temperatures, be prepared. Use of
extreme service moly wheel bearing grease in front bearings is
mandatory. I recommend Red Line wheel bearing grease. Read
the General Motors wheel bearing service manual, it states:
“Create a ‘dam’ of grease on both sides of the bearing to retain
hot grease in place in the bearing races.”
Absolute Must: *The wheel* is the radiator for most Porsche
brakes, especially the fronts. The contact patch between the hub
carrier and the rotors, and between the wheel and the hub carrier
must be very clean. A *thin* coat of silver or copper anti-seize
on the flat mating surfaces will serve as a conducting "bridge"
between the wheel and the mating surfaces. This attention to
wheel conductivity is worth almost as much as (in some applications
more than) ducting cool air.
Remember, you do not go fast using the middle pedal, so use it
earlier, and use it less. You will be amazed at the difference it makes.
All this talk about friction leads nicely into the need to bleed
your brakes. You should bleed or flush your brake fluid often if
you drive hard on the street or track, so an efficient bleeding
technique helps quite a bit. There are three types of "one person”
brake bleeding systems that I would like to familiarize you with.
Photo by Matt Platts
Downside: The first time I needed to use these they failed,
clogged or otherwise stuck, and the originals were sitting on my
workbench hundreds of miles away.
2) Vacuum Bleed - A vacuum system pulls fluids (including
air) from each bleed zerk. Upside, less moisture in the fluid.
Downside: I could seldom make this system work reliably, and if
it did, it emptied the reservoir (this system really sucks).
3) Pressure Bleeders: Motive et al. I made one of these from
a garden sprayer before they became readily available, then I
bought one. Downside: The reservoir cap gasket easily deforms
on the commercial one I bought, so special care was needed to
keep the gasket intact. If the gasket doesn’t retain a good seal, this
system can easily make a big mess.
Example of a vacuum bleeding system
Saturday, July 12th, 11a.m.-1p.m.
101 E. Hunt Street, McKinney, Texas
Photo by Matt Platts
Example of a pressured bleeding system.
(Sample provided by Zims Autotechnik)
Here is a quick summary that will explain the major differences
between them. This may help you to decide which system
is the best choice for you.
1) Speed Bleeders – This system uses a ball check valve built
into the bleed valve. It allows you to open and pump the brake
pedal until the old fluid is flushed, then simply close the valve.
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