[s-cars] Master cylinder help

[Tom Green]

I don't believe I would start with the brake master cylinder,  
especially if I wanted to
conserve resources.

One immediate problem is that this lengthy post has provided very  
little hard
information about the problem.  You have some definite idea just what  
this
pulsating brake pedal problem is, but you have provided the list with  
very little
solid information.

Does the brake pedal pulse only when the pedal is depressed?  Does the  
vehicle
have to be in motion and the pedal pulses while it is braking to a  
stop?  Or, does
the pedal pulse when the car is stopped?  But the engine must be  
running?  When
the vehicle is in motion and is being braked to a stop, do the braking  
action on the
car pulse as well, or is it just felt in the pedal?  Does the  
passenger feel the braking
action pulsing also?

I am not certain by any means that such answers will help solve the  
problem, but
it is a start if it includes any other abnormal operation of the brakes.

There are several individuals parting UrS vehicles and announcing it  
on the
UrS cars forum on Quattroworld.com.  That should be a source for  
inexpensive
parts.

Tom '95 S6
          '95.5 S6 avant
Knoxville, TN


On Monday July 25, 2011, at 1:16 PM,  Serge Filanovsky <s6serge at verizon.net 
 > wrote:

> Hi everybody, its been a long time since my last post. My S6 avant  
> came to
> an abrupt demise via a Japanese sh!tbox-- the cell-phone-clutching,  
> upstate
> New York lady came down to the big city to blow through a red light  
> and take
> out my driver's side front (enough for the Gecko to say its a total  
> loss). I
> had a car full of people, an no one was hurt. These cars are truly  
> tanks.
>
> But this is a tale of hope and resurrection. The car sat at my  
> mechanic's
> for less than a week, and a young lad from the neighborhood decided he
> wanted to fix it up. I had a few parts need for the fix (along with  
> all RS2
> bits) Rossato-Binned in my basement, so a deal was struck. A few  
> months, 2
> new headlights, and a whole lot of elbow grease later, the car was  
> back on
> the road! Looked damn good too!
>
> But trouble was brewing in the braking department. A pulsating pedal  
> that
> neither I or my mechanic could track down (tried new bomb or 5, new  
> pump,
> new hose, flushed the system 5 times... pulsation is still there,  
> worse
> during summer months--high humidity--less so in winter, has been the  
> only
> clue) had gotten so bad, that the car is now parked (also coincided  
> with the
> failure of power steering hose, which has been sent to Spokane House  
> of
> Hose), and the fluid reservoir caming off the master cylinder,  
> spilling all
> the brake fluid...I'm surprised lightning didn't hit it twice just  
> then.
>
> So my young friend is desperately trying to get the car back  
> together in
> time for his FIRST S//Fest attendance. But brake system  
> frustrations, and
> lack of sleep (and funds) due to a brand new baby, have him seeking
> desperate measures. He's considering converting to vacuum assist for  
> the
> brakes ala non-turbo 100. Not being a big fan of vacuum assist on  
> turbo cars
> (I know its been done), I'm trying to convince him to try a new  
> (different)
> master cylinder first.
>
> That's where you guys come in. I'm looking for:
> 1) any thoughts on brake-pulsating problem
> 2) anyone who has a good-known master cylinder in their Rossato-Bin,  
> or
> knowledge of where one can be sourced cheaply (dealer price is  
> something
> like $600 + the new baby)...
>
> As always-- TIA,
>
> -Serge
>
> '03 S8