[s-cars] Master cylinder help (long)

[Matthew Russell]

Serge!
Now by pulsating, do you mean like when you apply the brake and you  
can feel the pump pulses especially when the system is low on pressure?

Or pulsation like when the ABS kicks on?

My first instinct was to suggest one of the abs sensors in the front  
hubstrut housing isn't sitting in there properly, BTDT as I sounds  
like some major front end repairs were completed.

But now I'm not so sure...
Matt, CO
s6 a


On Jul 25, 2011, at 1:00 PM, Serge wrote:

>
> Message: 4
> 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