Heat temper brake pads

Fri Nov 14 15:24:46 PST 2008

I wonder if the heat tempering is suggested in lieu of the proper bedding in
process. 

I performed a very diligent bedding in process only once.  It was on my V8
5spd and in preparation for a towing event.  I installed new rear rotors and
Mintex Red pads all the way around.  The UFOs up front were still in very
good shape.  I spent a good hour and was very deliberate about my route and
the usual heat and cool cycles.  I'm sure I caught the attention of a few
people but I managed to complete the process w/o any issues.

To this day, that car has the best feeling brakes of every other one of mine
except the Avant which has Porsche brakes up front.  I don't know how much
of it is due to the type of pads or the bedding process.  I will use Mintex
Red pads in the future though.  

Ed

> -----Original Message-----
> From: quattro-bounces at audifans.com 
> [mailto:quattro-bounces at audifans.com] On Behalf Of Mark R
> Sent: Friday, November 14, 2008 3:13 PM
> To: Mike Arman
> Cc: quattro at audifans.com
> Subject: Re: Heat temper brake pads
> 
> 
> Mike,
> 
> I have a wholesale account with a big east coast tool 
> distributor.  The problem is that whenever I place an order, 
> I end up spending WAY too much money on personal tools... so 
> I feel your pain!  $4.00 book with some good tips... sounds 
> like a "score" to me!
> 
> The goal is to maximize braking efficiency and torque.  After 
> all, pads and rotors will work (in a diminished capacity) 
> without any "break-in" procedures.
> 
> Baking pads would work to burn off organics (greases, oils) 
> and you'd want to be near the top of a toaster oven's range 
> (375-400 degrees F, give or
> take) for 20-30 min.  Of course, this may or may not leave 
> toxic residue in
> your toaster oven.   =)
> Oh, and backing plate paint would probably start to burn off, 
> especially on a street pad.
> 
> OK, so this might be a good way to "break-in" a set of 
> pads.... but the racers and technical folks among us call the 
> necessary process something else.  "Bedding in the pads."
> 
> A critical part of the bedding in process is to heat up the 
> pads enough to burn off things (organics, binding compounds, 
> etc.), but that's only 1/2 of what's going on at the pad.  On 
> a more minute level, I'm told the friction material is softer 
> during this process which allows for two things: 1.  
> Directional alignment on a molecular level (which may or may 
> be bogus... I've never seen electron microscope scans to 
> prove this out). 2.  Increased pad wear to match the pads to 
> the rotors (high spots are quickly worn away so that there is 
> even braking force between the pads and rotor as wall as 
> maximizing the available surface area).
> 
> I do know that some pad manufacturers have had verbiage about 
> only putting pads back onto their first installed position 
> (no flipping in/out, axles, or left/right).  I have no idea 
> if this is due to even wear with the rotor (likely), or the 
> possibility there is in fact some form of molecular alignment 
> increasing the bonding of the friction material.
> 
> The other critical side of the equation is what's going on at 
> the rotor.  At the rotor, some material is embedded into the 
> face of the rotor and increases the coefficient of friction.  
> This is "bedding in" as pad material is evenly deposited to 
> the rotor face.  Baking the pads before hand might preclude 
> this process from occurring.  I see faint pad outlines on 
> rotor faces frequently.  Localized transfer has occurred, 
> causing a hard, high spot.  With sensitive brake systems, you 
> can actually feel it in the pedal as a pulsation.  The pad 
> face temperatures when bedding in (even for a street pad) 
> would exceed a household oven's temperature.  My track pads 
> aren't supposed to lose their friction until 1250 degrees F 
> (that's face temp, not backing plate or caliper temps).
> 
> I can see a few situations for baking a pad in an oven.
> 1.  Where bedding in is impractical or dangerous (like on an 
> airplane where there's not enough runway to safely heat up 
> the brakes). 2.  Where rotors preclude normal bedding in 
> processes due to their coatings.  ATE slotted rotors come to 
> mind since I've installed a bunch of those, including on my 
> Escalade EXT and my mother's BMW 330ix. 3.  Decontamination.
> 
> Make sense?  Anyone else has thoughts or experience on the subject?
> 
> Mark Rosenkrantz
> PA-28R-200 based at CZG, Endicott, NY (so I've not purchased 
> Mike's book on C-150s, yet). A few Audis. a trailer, and a 
> few American vehicles.
> 
> 
> 
> 
> On Fri, Nov 14, 2008 at 4:17 PM, Mike Arman 
> <Armanmik at earthlink.net> wrote:
> 
> >
> > Two places I should never go when I have cash in my pocket - tool 
> > stores and used book stores.
> >
> > Anyway, bought a copy of a hot-rodding book by a guy named Wayne 
> > Scraba, bunch of tips and tricks for the go-fast crowd, best $4.00 
> > I've spent in a LONG time.
> >
> > He talks about putting new brake pads in a toaster oven 
> (not one that 
> > you ever plan to cook food in
> > again!) and heating them for 30 minutes to temper them - drives off 
> > the VOC's, sets the adhesives, etc.
> >
> > He omits to mention how hot.
> >
> > I've been all over the internet looking for this one last (vital) 
> > tidbit, and can't find it OR him - I did find an e-mail for 
> him but it 
> > bounced back as unknown.
> >
> >
> > Anybody know anything about this? How hot should I be 
> baking new brake 
> > pads? Or is this "old-tech" and we don't need to do it any more?
> >
> > (And I think this might also be applicable for bonded shoes on drum 
> > brakes,
> > too.)
> >
> >
> > Best Regards,
> >
> > Mike Arman
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