Aztek 2001 FWD, front rotors, rear drums.
As an opening note, this is a problem that has been with this car since
the delivery day. Three GM dealers and one independent garage had their
hands on this, but no one could ever fix it.
Ok... Here we go...
The problem is a kind of vibration or shuddering when I apply the brakes.
It is mostly noticeable when I drive downhill and/or when I drive at 100
km/h (did I mention I am Canadian!?!?) or more and press the brake pedal.
The shuddering will start when the speed decreases below, let say, 70
km/h and until the car stops. It is not always easy to tell, but at
times, the shuddering is clearly happening mostly at the rear right
wheel. Driving in the city, it is rarely noticeable unless I apply the
brakes strongly. My brake pedal has always been spongy and I have to push
harder than any other car I ever owned or rented to bring the car to a
stop. If I just apply the parking brake pedal on the highway and go
slowly from, say, 110km/h to 60km/h, the shuddering is even stronger, to
the point that the rear of the car starts seriously bouncing. If I drive
below 60 km/h and apply the parking brake, then the shuddering is not so
clear. Of course, this is an average description since the behaviour will
vary depending on how hot the brakes are. Also, I noticed that it seems
worse on a humid or rainy day. I must mention too that I engage my
parking brake every time I leave the car as an old habit I acquired when
I had a house with a sloping driveway (GM mentioned at some point that
this might be causing the problem?!?!?). Lastly, I am not sure if this
helps, but the brake pedal does not pulsate much (or not at all) when the
The different mechanics that worked on the car have been content with
playing with the rotors/pads/drums/linings till we are all blue in the
face but this never solved the problem. They have turned and replaced all
these parts quite a few times through the years. Typically, when I start
fresh with a new garage, the mechanics diagnoses the shuddering and,
right away, he wants to play with the front rotors/pads. When I complain
that it really seems to originate from the back, he then wants to play
with the drums/linings. The only constant fact here is that no one, I
mean no one has ever given a thought about looking for other causes. I am
running out of options and my extended warranty is ending soon. I want GM
to acknowledge the problem and most importantly... Fix it! I wasted so
much money and time on this issue, it is just driving me insane.
Here are some questions:
- From the description, can one conclude that the problem is at the rear
and not at the front? I am basing my assumption on the parking brake test
and the fact that when regular braking is very bad, the shuddering is
clearly coming from the rear wheels (mainly at the right).
- Since the parking brake causes the shuddering on its own, doesn't that
eliminate the hydraulic system from the equation?
- My present dealer says that the problem has to be with the brakes since
it happens when I apply the brakes. I think this is simplifying the
issue. Can someone point me to a list of possible parts that could be the
culprit since I am no mechanics myself (how about the hardware, backing
plate or others...).
- Does changing the linings always mean changing the shoes too? I thought
the linings were glued to the shoes by the manufacturer?