My daughter in North Carolina has brought forth a typically vague complaint
of a brake problem on her 2000 Alero. Old dad will be packing up the tool
box and heading south next week to investigate.
Have never worked on a vehicle later than a '92. Do the brakes on this
Alero require any special tools, tricks, or knowledge for someone like me to
work on them?
only real tricky part is the ABS system. If you push the pistons in the
calipers back to replace the pads loosen the bleeders slightly to allow the
fluid to come out there rather than push back up into the system and turn
the ABS into an expensive filter. Also some abs system require a scan tool
to bleed is you happen to get air in the lines.
This is false! I have never seen any damage done to the ABS system
and I've been performing brake repair work since the advent of the
ABS systems that we have around today. There is no such warning
in the service manuals (about not pushing the brake fluid back into
the ABS controller while retracting caliper pistons) and there has been
no mention of this at any training course that I've been to.
Chrysler service manuals have that warning (bendix system specifically) and
my S10 manual specifies a scan tool is needed to properly bleed the whole
system so without a manual for the specific vehicle he's talking about its
better to play it safe and be careful.
I'm talking strictly about the "damage" to the ABS system if
you don't open the bleed screw while retracting the caliper
pistons. Using a scan tool to bleed is another issue altogether.
But again, I've never had to use a scan tool to do a common
brake job...so that won't be an issue for the OP...unless he
takes your advise and starts opening up bleeder screws and
manages to get air in the system.
As far as the Chrysler service manuals saying what you say
"they" say....I'd appreciate a cut and paste on that one. I'd
be interested to see this in print.
I learned my lesson and got rid of the chrysler as soon as I paid it off,
put all the manuals in it. At the time preventing fluid from being pushed
back up into the system was a common issue with the ABS on those. Many
people reported ABS failures after a non chrysler tech changed their pads
and pushed the old rusty fluid back up into the ABS system. Seems one of
the many design flaws with that system was the lack of a check valve to
keep fluid from going back in this very situation and any dirt/rust in the
fluid would cause problems. I changed my own pads (yearly on those
underdesigned brakes I might add) and never caused a problem with the ABS
but I did have the pump seal failure and an electrical failure with the ABS
which was fixed by the warranty recall.
I have been told that better ABS systems have check valves to prevent fluid
from pushing backwards when compressing the calipers but I haven't yet
taken apart an ABS system or seen disassembly instructions specifically for
it in a manual (don't have a factory manual yet for my s10) but I've
followed the practice of opening the bleeders just enough to get wetness in
the hole but not enough to let the fluid run out by itsself and then
compressing the caliper and the partially open bleeder will let the fluid
squirt out (best to use a hose and bottle, a one man bleed kit is cheap and
works here) rather than pushing it back up in the system.
BTW this question comes up every so often in many NG's such as this or web
based forums and the answer seems to be split 50/50 agreeing/disagreeing
with what you saw. Many mechanics and non mechanics with varying years of
experience will say "won't hurt the ABS" but just as many mechanics and
non-mechanics with varying years of experience will say "be careful you
could cause problems in the ABS system".
Don't want to get caught in the middle of this discussion, but while
perusing the Bendix site to scope out their brake pad product offerings I
stumbled upon this article on the subject there:
Bendix is the OEM for many makers. The Chrysler I had was a system 10, but
GM used a system 2 at one time or another. It could also be possible that
you and other tech you know have just been lucky and haven't caused any
Being the maker does not mean that they write the manuals and/or
repair procedures. And as far as me...and every other GM dealer
tech in the city being lucky ( I say this because if there was a real
problem with this, there would have been a service bulletin about
it, or the training center in the city would have brought the info to
everyone's attention and they haven't), I highly doubt this.
If you drain someones antifreeze to replace a waterpump or hose and you see
rust and dirt in the bottom of the buck you drained into do you pout that
rust and dirt back into the radiator when your finished? Maybe there isn't
a bulletin because its common sense. Many of the posts I;ve read or
mechanics I've talked to say its not a good idea to push the potentially
dirty fluid bake up into even a non ABS vehicle. Your wouldn't pour dirty
antifreeze back in the radiator or put dirty oil back in the engine would
you. The original poster asked if there were any potential problem to look
out for and I simply pointed out something that I've been told/heard. been
careful of when I've done the job. No person can know everything that is
why I read and see what suggestions others have or mistakes others have
made. I used to use Fram filters for example and thought the leaky one I
had was just a fluke thing until I started to notice how many other people
had problems with them. Thats just one example of something else I learned
from others problems/mistakes that I don't have to make the same mistake
Well, we have a technician in our shop that happens to have worked
in a Chrysler dealership for about 15 years...I'll ask him what they
did where he worked. As it happens...I also worked at a Chrysler
dealership about 10 years ago. I worked there for 4 years...never
encountered this problem...never saw or heard any documentation/
training to indicate that this procedure was required.
Yep...I've heard some technicians say this (online...never have met any
in real life that experienced this). Until it bites me personally, I will
to chalk it up to some mechanic having an ABS failure right after a brake
job and thinking that it was connected. We all do that in this trade...we
see something happen once, and for a long time after that, we will modify
our procedures thinking that "that" particular problem will re-occur again.
Often it never does, was a one-off....or was not even related to whatever
what does the scan tool do? what information does it show that the involves
the bleed process?
i'm not sure why the abs needs to be monitored.
does it tell you the piston position in the caliper or if air still remains
in the caliper?
i would assume that after a bleed, the ABS check light is sufficient enough
to alert any problems.
It cycles the different valves inside the ABS system to allow the air to
escape according to my service book.
I've been extra careful to make sure I don't allow any air in so I don't
have to go somewhere and have it bled.
If air enters the ABS modulator unit then it may be necessary to use the
scan tool to open up all of the valves in the modulator to bleed it out.
However, I can't see this happening on even a typical caliper replacement,
let alone a brake pad replacement.
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from firstname.lastname@example.org
There is no need for any scan tool for a normal
"replace the pads, machine the rotors" type of
brake job. But you will hear plenty of people
on newsgroups blowing smoke up people's ass about
this sort of things.
Scan tools are occasionally needed to "bleed" the
brakes on "some" models with ABS. I've run into
very few that actually need this. The late model
Cadillac's do...and I've done a few of these...so
I am familiar with/know the procedure...but it cannot
be said that a scan tool is needed on every brake job.
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