Bernie Benz b.benz at
Tue Aug 24 13:41:10 EDT 2004

Don't believe me OK, but who's your kook that convinced you that MC seals
swell with heat?
MCs are much less prone to "Seals, scored pistons from crud build-up,
failures, whatever the reason" failures than are calipers, from lack of
proper maintaince.  Air in the system is much more prone to temperature
changes than is brake fluid.  Overhaul your MC and then bleed the system


From: SuffolkD at
Date: Tue, 24 Aug 2004 11:25:58 EDT
To: b.benz at
Cc: 200q20v at
Subject: Re: after

Bleeding Air out of the system HAS absolutely nothing to do with it Bernie.
Why would heating "air" have anything to cause brake drag.  That's about as
useful as considering air to be a beneficial aid in applying brake pedal
pressure to the calipers in a hydraulic system.
Not a symptom. 
Not the answer. 
These MC's are replaced in high mileage cars.  Seals, scored pistons from
crud build-up, failures, whatever the reason.
Air gives a spongey pedal and inferior braking performance. Not increased
performance when hot (like you suggest) from my post:
"Phil & listers: 
Its been explained to me as the MC seals swell from the heat from the
My pedal will drop resistance free an inch, then take up normal braking
OR be rock solid the entire travel when the brakes are dragging (from the

Interestingly, its solely temperature related.  80 plus ambient with engine
temp in the middle.

The last ten feet or rolling to a stop is the tell tale sign.  Either the
car rolls back and forth after stopping, or the car grabs and holds

Temp fix is to do-rag the MC soaked in water, avoid stop and go traffic.
-Scott by BOSTON" 

Symptom:  ALL FOUR brakes drag when the radiator fan is blowing HOT air on
the MC and under hood temps get really high.
No two ways about it, when it cools under there, the brakes no longer
Its NOT a single line subject to manifold or turbo heat.

Phil has traced his soft pedal to a leak on his hard line under the car.
Reasonable cause/explaination given "his" symptoms.

Unfortunately, I've been experimenting with this for months now.
Park the car HOT and dragging, let cool and then I can roll the car by hand
on a level surface. - Scott by BOSTON

In a message dated 8/24/2004 10:36:14 AM Eastern Daylight Time,
b.benz at writes:

Bleed ALL of the air out of the system, Scott.

More information about the 200q20v mailing list