Re: Brakes

[RC Ringlien <rringlie@isd.net>]

Al Powell wrote:
> 
> Bob - the pressure sensor for your hydraulic system is not in the
> bomb - it's screwed into the bottom side of your master brake
> cylinder.  Take a look and you'll spot it - it has two wires
> connected.
> 
> Generally if the brakes are coming on when the car is hot, it's
> caused by an internal leak in the MC allowing fluid to expand.
> The remedy is to replace MC.
> 
> *******************************************************
> Al Powell, Ph.D.                 Voice:  409/845-2807
> 107 Reed McDonald Bldg.          Fax:    409/862-1202
> College Station, TX 77843
> Http://agcomwww.tamu.edu/agcom/satellit/alpage.htm
> *******************************************************
Al:
   Thanks for the reply.  Some confusion here about the sensor for the
hydraulics.  The earlier post about sensors was a reply from Phil,
trying to identify my setup as he didn't have documentation.  My
hydraulic sensor is a 2-wire deal on the servo, not on the MC--probably
what you meant?  Anyway, I realize that the master cylinder is the final
arbiter for appyling the pressure, but why the loss of boost during this
dragging?  The pedal gets hard and system appears strictly mechanical.
Dewitt:
   It is good to know that Mr. Russell's exact(?) problem was fixed with
servo replacement.  However my servo passes the disconnected return hose
test.  No fluid leaks back with engine running and foot OFF the pedal. 
During the last failure, there was no obvious turbulence in the
reservoir as there should be if the servo was leaking internally.  So
far I have 2 votes for the MC and 2 for the servo.  Another lister had
replaced the servo with this problem; it turned out to be the bomb and
he refitted his old servo!  My light does blink when I stab the pedal
and is very slow to go out during start-up.  I better recheck the # of
pumps it holds before losing boost.
   I may remove belt from the pump, get car hot, muscle it around for
4-5 miles to see if they start dragging.  If problem returns, I'd vote
for the MC, otherwise the servo.  Is this GARAGE LOGIC?  Using Audi god
logic, of course means it's the bomb !!
Bob Ringlien
rringlie@isd.net