In Reply to: Actually, what IS the deal with this? posted by Eric on October 26, 2000 at 22:34:58:
Based on comments from the amazingly
perceptive members of this forum, and my
working knowledge of automotive braking
systems, here's my opinion:
There are two potential concerns with
bleeding your own brakes, in a system with
ABS and/or AST. The presence of either of these
systems adds additional plumbing to the
hydraulic portion of your brake system.
1) If you allow air to enter the system, it can
work its way into these additional components.
If that happens, you could have what appear to
be normal braking power, but with compromised
ABS or AST functions. The dealer has a system
that cycles these additional components to
remove any air that might get in
2) Merely pumping the pedal or pushing fluid
thru the system from the resevoir will not
cause fluid to move thru these systems.
Therefore, when you do a fluid change at home,
not all the old fluid get's flushed out.
Is that a concern? Well, if the fluid in
that part of the braking system gets
sufficiently contaminated with moisture such
that it degrades the ABS/AST valves, it might
cause a degradation or failure of those
Find out what your dealer/mechanic charges.
Mine is very inexpensive, so I just let them
take care of it at the same time they
flush the cooling system, and change fluids
in the transmission and differential. I love
working on cars, but I'm to lazy to deal with
the messy fluid flush stuff.