[s-cars] Brake Fluid Equalizer

[cobram at juno.com]

It's not an equalizer, a Colt 45, that's an equalizer. ;-)
 
It's the Proportioning Valve, it's a kind of restrictor which only lets a
certain portion of the pressure through to the rear wheels, since the 
front wheels need more braking force because of inertia.  Most of them
consist of a plunger/spring setup.  If it wasn't there the rear wheels
would lock up when you hit the brakes.
 
It's not a common Audi failure point but has shown up on the list once in
a while.  Yours sounds like it was gummed up, or you might have had a
blocked line (Monday night quarter backing here.)  You might have been
able to clean it out and put it back....but that's if you were doing  it
yourself, if you're paying a tech they'll just change it 99% of the time.

I suppose low pressure to the rear calipers could cause the kind of wear
you indicated.  Take it out for a spirited ride and hit the brakes hard,
check the rotor surfaces, if the inner surface is still not making
contact,  you problem probably lies with the calipers.
 
BCNU,
http://www.geocities.com/cobramsri/
We come into the world naked, screaming and covered in blood. Why should
the fun end there?
 
 

"Max Hoepli" <mhoepli at vif.com> writes:
> Hi all,
> 
> Just had the original brake fluid equalizer/proportioner [C$355] 
> changed. Found in front of the left rear wheel.
> Anyone know what the equalizer has inside? Mechanic says equalizer 
> was seized, practically only the front brakes were working. Anyone 
> can give some knowledge of the function of the equalizer? The car 
> with the old equalizer was making boing-boing spring noises at the 
> back, most noticeable in an underground garage. With the new 
> equalizer very smooth, quiet boingless braking.
> The rotors in the back were rough, rusty on the inner surfaces. only 
> the outer surfaces were touched by disc pads. 
> 
> Should the mechanic 3 weeks earlier who changed the front brake 
> shoes C$135 and both front rotors, each C$140 have noticed that the 
> equalizer was defective? The car was making rubbling noises when the 
> brakes were applied after this service, with time I was aware that 
> this noise was coming from the back, which prompted me to see my 
> other mechanic.
> 
> There has never been discussion of the brake fluid equalizer as far 
> as I know in this group.
> It seems to me it might be a good idea to grease the shoulder joint 
> of an equalizer to prolong its life.
> 
> Max
> 1986 Quattro type 44