[s-cars] Hydraulic brake problems, more

[Wayne Dohnal]

> At this time I have basicly no brakes, the mechanic is telling me that
> the master cylinder, brake booster and brake presure accumulator all
> need to be replaced because the Pentosin has damaged them.

Chris,

I feel uneasy going up against a professional mechanic, but something isn't
right here.  The nice thing about the list is that if I have my wires
crossed and say something untrue you can be sure that others will post
corrections.

First off, the S-cars do not have a "brake pressure accumulator".  They have
a "hydraulic pressure accumulator", AKA the bomb.  I sure hope that Pentosin
doesn't damage it, because that's what it's meant to be used with.  I have
no clue what the "brake booster" is, unless it's a subassembly attached to
the master cylinder.  I'd be very suspicious of someone who gives detailed
advice about a system they do not understand the workings of.

I'm totally clueless if the Pentosin would have damaged the brake
components.  I have heard that petroleum products are not good for the seals
in the brake system.  But if the master cylinder is damaged I don't
understand why the wheel cylinders wouldn't also be damaged (unless you
didn't add a whole lot of Pentosin and it didn't travel down to the wheel
cylinders).  And you also have to ask what the ABS unit, clutch master, and
clutch slave think of all of this (I'm clueless here too).

If I were in this dilemma I'd first try to research the issue of potential
damage to the seals in the brake and clutch systems.  I'd get a couple of
liters of cheap DOT3 fluid and do a real good flush of the system, including
the clutch.  If things got better, I'd flush it again with the proper DOT4
fluid and hope that there wasn't any long-term damage done, especially if it
could result in the pedal going to the floor when you need to stop the car.

Wayne Dohnal
1994 S4