Anti-Lock brakes - How should they feel?

[Chris Chirdon]

Vehicle:
1993 Legacy Wagon 4WD w/ABS

Description of the problem:

Anti-lock brakes are new to me. This is the first car that I've had
equipped with them. I went to a local huge parking lot the other day after
it snowed 5+ inches to see how they work (and see how the 4WD worked as
well). I got up some speed and hit the brakes, and the (usually otherwise
firm) pedal went all mushy down close to the floor and I heard this sound
that was a steady pulsation/creaking, but was fairly loud. I could feel it
through the pedal and hear it through the firewall. It sounded like a loud
regular creaking/clacking noise somewhere about 15-20/second.

Now, the theory is sound. This is the Anti-Lock system pulsing the brakes
for me. And it did seem to work. But 2 questions:
1) is my brake pedal supposed to go all mushy during anti-lock operation?
2) the creaking/clacking/buzzing was so loud that my wife released the
brakes once on a slippery road, thinking the car's brakes had broken. Is
the anti-lock system supposed to be this loud? I kind of figured one would
hardly be able to hear it. it's not terribly loud, but it's loud enough to
make you say "what was that and is something broken?"

Mainly I just want someone to verify that this is how the system is
supposed to sound/feel or not. We have been having problems with the brake
calipers on this car, and just replaced the 2 front ones because they were
absolutely frozen (rusted slide pin). I want to be sure that we didn't
misss something.

Thanks oodles,
Chris Chirdon
Pittsburgh, PA

[Josh Colombo]

Chris,

This is how ABS works. Pedal will go to the floor during an ABS
activation event.

It sounds like everything you said is working fine. I would recommend
flushing the brake fluid. It will help in pedal feel & brake
performance.

Here's a site with moocho brake info.
http://mysite.verizon.net/romano.michael/

Check out this site for ABS info
http://www.geocities.com/nosro/abs_faq/

I don't have ABS....so I can't tell you how loud it should be.....but
the ABS motor will make noise. Key with ABS is.....keep your foot in
it.....don't let off, pump the brakes.

Josh

[Samuel Reed]

Here's my favorite quote from that informative ABS article:


"The Subaru ABS behavior seems a bit erratic and I have not quite figured out what trade-offs the engineers had in mind."


That's what I'm sayin'


Sam