98SL2 brake troubles, dealing with the dealership service dept

I had my 98SL2 (~74K mi) in to the local Saturn dealership about a month
ago for an oil change. They found several problems, some of which were
covered under the extended warranty, and a couple that weren't. All
told, I walked away having to shell out over 500$ for what was supposed
to be an oil change*.

One thing that was covered was both rear brake wheel cylinders were
leaking fluid. They supposedly fixed that. However, I had to take the
car back two days later because the brakes weren't bled properly - the
pedal had excessive travel and was mushy.

I'm taking it back in tomorrow because since they bled the brakes, the
car shudders when I brake, especially at highway speeds (ie, getting off
the freeway.) I can feel it most in the pedal, but also in the steering
wheel. The shuddering is a rapid pulsing which seems to maintain
frequency but drop intensity as I come to a stop. It isn't a violent
shaking, but the brakes simply don't feel right at all.

Warped rotors and improperly installed calipers are two causes of this
behavior, IIRC. Are there other possible causes? How would you
approach the service manager when you take your car in (for the third
time in a month)? I don't want to be a jerk or another irate customer,
but I am aggravated that

a) I don't remember noticing or having this problem before the
dealership worked on my car, which makes me wonder if it is something
they did or didn't do correctly
b) If the problem is something like warped rotors, wouldn't they have
seen that while I was there last time? Do rotors just suddenly up and
warp one day, or is it a gradual process?

Thoughts/comments/suggestions?

tia,
-rj

* I usually don't take it to the dealership for just an oil change, but
every once in a while I will just in case there are things which need to
be taken care of, like this time.

 

I can comment to piece of your post... I've warped them in a single event.
Anytime the wheels come off and I don't care who does it, I drive easily for
the first 30-50 miles and then retorque the wheel nuts. Usually only the
fronts have backed off, however this last visit both fronts and backs took
retightening...

 

Turned out to be warped/worn rotors. They weren't covered under any
kind of extended warranty, but apparently Saturn of Columbus warranties
these brake pads for the life of the car, despite the fact that they're
a wear item.

They showed me the rotors and the tech (saturn mechanic) mentioned
something about "metal transferrance" between the rotors and the pads if
the vehicle sits to long. He said he didn't know why it happened, but
that it did. Can anyone shed some light on this? Just curious.

-rj
98SL2

 

This article touches on it:
http://www.stoptech.com/whitepapers/warped_rotors_myth.htm

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