[W126 Coupe] brake bias adjustment

[Shayegan, Richard]

The lack of having a progressiveness to the brake pedal feel is the
result of using ceramic based pads. Changing the rear pads to match the
front will help the bias issue, but if you want a brake feel that is
more progressive you have to go to a metallic pad, but these tend not to
have as good fade resistance as ceramic pads. I wonder if your race
class would let you take out the fog lights and run ducts from them to
the front pads?
Richard


________________________________

	From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Divov
	Sent: Monday, February 19, 2007 4:11 PM
	To: Mercedes Coupes Mailing Lists
	Subject: Re: [W126 Coupe] brake bias adjustment
	
	
	We tested the car on the public road.
	This front lock up is occurring under 'normal' road conditions
where the brakes aren't even particularly hot.
	We tested it on the freeway and at 140kph (+-90mph) stomped on
the brake pedal and she locks up (particularly one side) front wheels.
	With the standard pads & set up this would never happen.
	The lousy part about it while racing is that the brakes don't
have a progressiveness.
	From not stopping particularly strongly, she goes into wheel
lock-up which is really not what you want because you then have to get
off the brakes & start again and -  you are now flying into a corner
much too fast...
	It can all get very messy, very quickly.....
	 
	The way I race is I apply brakes strongly (at the limit of
adhesion) at the last moment whilst still in a straight line and then
gradually taper off my braking action for about the first 1/3 of the
corner at which point I transition to ever increasing acceleration and,
if all goes right, I'm at full throttle as I am exiting the corner. Its
clean & fast.
	To drive this way I can't have brakes locking up prematurely.
	 
	Maybe I must also change the rear pads to Ferodo Ceramic and
re-bleed my brakes just for good measure.
	At this point, the problem isn't over-heating brakes or brake
fade - its too much braking to the front wheels.
	 
	So there isn't a valve arrangement which senses a weight
transfer on the W126's? (or something like on many pick-up trucks?)
which changes brake bias?
	Thanks for your input.
	Regards
	Alec

		----- Original Message ----- 
		From: Jonathan Hodgman <mailto:jhodgman at gmail.com>  
		To: Mercedes Coupes Mailing Lists
<mailto:mbcoupes at mbcoupes.com>  
		Sent: Monday, February 19, 2007 10:01 PM
		Subject: Re: [W126 Coupe] brake bias adjustment

		I would also consider switching to either a cryo treated
rotor or some aftermarket rotor that's harder.  MB uses soft pads and
rotors & I'm sure your new pad was designed with a much harder rotor in
mind.  
		
		You would need to buy a bias adjuster and mod it to fit
out cars..although I'm a bit surprised you are having the problem.  
		
		Have you considered adding some ducting to help cool
your brake system to help w/ the fade? 
		
		Jonathan
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