'95 900SE brake issues

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Hans L - 28 Jun 2004 23:35 GMT

Hi,

I'm wondering if anyone can tell me what might be wrong with my brakes
on my auto '95 900SE(V6). The basic problem is that the brakes are very
low and very soft -- I have to push down quite a ways to get the car to
stop. I asked the dealership on a couple occasions about this, but was
told that "brakes are brand new & there's nothing wrong!" (and perhaps
they need to "wear in" ... but that was a few thousand miles ago now).

So, I'd be happy to believe that, but the other day backing down a steep
driveway I was unable to hold the car using the brakes -- no matter how
hard I pushed. I had to use the hand brake to actually get the car to
stop rolling backwards.

Also -- and perhaps this is unrelated -- I can't seem to engage the ABS.
I was trying a bit this evening to come to a very sudden stop. I'd go
about 40-45MPH & slam on the brakes but no squealing or ABS shudder,
just soft pedal and car slows quickly (but doesn't slam to a halt). Oh,
and last I looked (pretty recently) the brake fluid was at the right
level (certainly the problem has been there since I bought it 6 mo ago &
fluid level has been checked several times). I haven't owned this car
that long, so I don't know what was done to it. Clearly the brakes have
been serviced recently (pads are new). Perhaps they didn't bleed it
properly or something (what would be the symptoms of that?).

Anyone have any suggestions of ways I can narrow it down? I'm gearing
up to bring it back to the dealership for the 90k service, so at worst
I'll have them look at it again then. It doesn't feel quite safe now,
knowing that i can't bring the car to a seatbelt-snapping halt.

Thanks in advance!
Hans

Reply to this Message

Charles Christacopoulos - 29 Jun 2004 02:39 GMT

> Hi,
>
[quoted text clipped - 28 lines]
> Thanks in advance!
> Hans

I don't know the effects of ABS but leaving that aside you can have a
number of possible problems (in order of likelyhood):

Air in the system ... which will result in a soft, long pedal. Try
quickly pumping the pedal if it rises and gets harder there is air in
the system. (You don't have to have the car moving to do this)

Master cylinder is on its way out and its piston(s ?) is leaking. It
means only a proportion of your braking gets through to the pads. This
would also result in a soft long pedal. The only time I had one fail
was doing the brakes on a classic 900 ... after pumping and pumping it
eventually got to the floor.

Contaminated disks (rotors) and/or pads. Would explain the car not
stoping but you would have a normal (hard) pedal.

... all sorts of other things I can't think of. Try the first test and
if it is not that then the problem is on the master cylinder.

Regards
Charles

Signature

Please remove _removeme_ to reply.
Work: http://www.somis.dundee.ac.uk/
Hobby: http://www.egothor.org/

Reply to this Message

Bob - 29 Jun 2004 03:17 GMT

>I don't know the effects of ABS but leaving that aside you can have a
>number of possible problems (in order of likelyhood):

I think the biggest problem is that your dealer is an idiot. Find an
independent mechanic or another dealer to fix your brakes properly.
If the other dealer just worked on them, talk with the new folks
who actually fix the problem and decide if you should send the bill
to the previous dealer.

Reply to this Message

Fred W. - 29 Jun 2004 14:01 GMT

> Hi,
>
[quoted text clipped - 4 lines]
> told that "brakes are brand new & there's nothing wrong!" (and perhaps
> they need to "wear in" ... but that was a few thousand miles ago now).

The biggest clue is "The brakes are brand new." You have air in your brake
lines. Bring it to be fixed somewhere else before you kill yourself and
some other innocent person.

-Fred W

Reply to this Message

Hans L - 29 Jun 2004 23:32 GMT

>>I'm wondering if anyone can tell me what might be wrong with my brakes
>>on my auto '95 900SE(V6). The basic problem is that the brakes are very
[quoted text clipped - 6 lines]
> lines. Bring it to be fixed somewhere else before you kill yourself and
> some other innocent person.

Thanks, Fred :) My explanation might have been a little dramatic (they
do feel low, but certainly in normal street traffic they stop the car
fine), but I have been driving my '91 900S (with very good, working
brakes but unfortunately non-working a/c) instead.

I will make an appt to have it checked out ASAP at a non-dealer shop
nearby. The only thing is that I did try the "pumping the brakes" test
and it did not seem to make make the brakes any higher/harder. There's
also a hissing noise when I push in the brakes (when car is on) --
sounds like i'm using a foot pump. I'm assuming that's a normal part of
the system, though.

My first assumption was air, though, because of the newness and air as
an explanation just "feels right" given the way the brakes behave.

Thanks everyone for the tips. It's off to the shop....

Hans

Reply to this Message

Timo Geusch - 30 Jun 2004 07:03 GMT

Hans L was seen penning the following ode to ... whatever:

> I will make an appt to have it checked out ASAP at a non-dealer shop
> nearby. The only thing is that I did try the "pumping the brakes" test
> and it did not seem to make make the brakes any higher/harder. There's
> also a hissing noise when I push in the brakes (when car is on) --
> sounds like i'm using a foot pump. I'm assuming that's a normal part of
> the system, though.

This may be normal (I haven't driven a GM 900 for quite some time) but
then again this may indicate a vacuum leak which would effectivly
disable the brake servo.

Signature

Timo Geusch
Morini Corsaro 125 | Bimota YB7 | Honda Pan European ABS/CBS/TCS
BOTAFOF #33 TWA#10
The UKRM FAQ: http://www.ukrm.net/faq/ukrmfaq1.html

Reply to this Message

Charles Christacopoulos - 01 Jul 2004 01:00 GMT

> Hans L was seen penning the following ode to ... whatever:
>
[quoted text clipped - 8 lines]
> then again this may indicate a vacuum leak which would effectivly
> disable the brake servo.

I would have thought the pedal would be hard (not long) and the car
would be still difficult to stop.

Signature

Please remove _removeme_ to reply.
Work: http://www.somis.dundee.ac.uk/
Hobby: http://www.egothor.org/

Reply to this Message

Fred W. - 01 Jul 2004 13:15 GMT

> There's
> also a hissing noise when I push in the brakes (when car is on) --
> sounds like i'm using a foot pump. I'm assuming that's a normal part of
> the system, though.

Yes, good assumption. That's the power assist you are hearing.

Air in the lines is best described as causing the brakes to feel "spongey."
It's as if you have to press the pedal progressively harder (and further) in
a non-linear fashion to get them to work harder. Versus the normal linear
action and response. Hope that helps...

-Fred W

Reply to this Message

Hans L - 01 Jul 2004 22:05 GMT

Thanks everyone for the helpful suggestions.

This morning I brought the car into an independent, local repair place
that specializes in Saabs & Volvos (I assume that's more of a "we love
Sweden" than a "these cars have common parts").

At first they also claimed that they were unable to reproduce the
problem. That the behavior seemed "fine" in the test drive & that maybe
it was an intermittent failing master cylinder. They did notice some
pitting on one of the rear rotors, however, which they thought might
have been caused by a seized caliper (or the other way around?).

A couple hours later I got another call. Apparently in proceding with
analysis the technicians discovered that both rear calipers had seized
and they had also somehow confirmed that there was a slow leak from the
master cylinder. Upwards of $1200 for the parts & labor; now glad I
bought that extended warranty...

Hans

Reply to this Message