Re: Brakes

[RC Ringlien <rringlie@isd.net>]

Al Powell wrote:
> 
> > 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?
> 
> Nope.  Only setups I've seen have pressure sensor on the body of the
> master cylinder.   Yours is newer than the ones I have seen, and is
> evidently different.
> 
> > Anyway, I realize that the master
> > cylinder is the final arbiter for appyling the pressure,
> 
> Not really.  Think about this: hydraulic pressure is supplied by the
> pump and a reserve of pressure is held in the bomb.  The MC only uses
> what's available, and does not directly affect 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.
> 
> You refer to BRAKE "boost/assist", not turbo boost, right?  If the
> light is on as you describe, it is an absolutely textbook
> indication of a bad bomb.
> 
> >  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
> 
> That's my vote.
> 
> 
> 
> *******************************************************
> 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:
   What we have here is a failure(slight) to communicate.  Pressures and
boost. It was brake LINE pressure(not hydraulic) and hydraulic boost(not
turbo).  Though I was a computer tech writer for a few years, I guess
I've lost my knack.  
   I spent the day scrounging boneyards for 89 200 parts with no luck. 
A friend may have a bomb I can try but is out of town.  I found a used
ISV for my daughter's 85 5kt for $20 so the day wasn't totally wasted.
   Thanks for your vote.
Bob Ringlien
rringlie@isd.net