Saturn has a whump whump and brakes are weird

Tiny
CBR74
  • MEMBER
  • SATURN
Had to borrow my friend's 2000 Saturn SL, 92k miles while my car is in the shop. The Saturn has several symptoms. While driving, it exhibits a mild whump whump sound and feel from the front end. While braking at low speeds the brakes kind of grab, release, grab release but no feedback through the pedal or steering wheel. When almost to a stop, the rear brakes squeek.
The front brakes are near new, the rears are thin but still within spec.
When off the ground and tires off, the whole brake assembly seems to "wiggle" and there's quite a bit of CV shaft wobble from side to side yet the axle seems to spin true. Warped rotors, bad CV axles?
Please help.
Wednesday, March 29th, 2006 AT 11:37 AM

7 Replies

Tiny
PEPPERMRJ
  • MECHANIC
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Not sure I follow
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Wednesday, March 29th, 2006 AT 3:59 PM
Tiny
CBR74
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Yes, the whole caliper/steering knuckle assembly wiggles under braking without the tire and wheel on the car. That's how I ruled out any problem with the wheels/tires.

I'm kinda figuring it's the rotors but I'd hate to be wrong.

I'll be sure to check that motor mount too.
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Wednesday, March 29th, 2006 AT 5:07 PM
Tiny
PEPPERMRJ
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For safety purposes always check the ball joint and upper control arm bushings while you're at it.

Let us know. :)
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Wednesday, March 29th, 2006 AT 6:36 PM
Tiny
CBR74
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Man I'm still kinda stumped. The disc is out of round by a bit, does that matter? What's getting me is that damn CV shaft wobble. Even with the suspension compressed so that it's level, it still doesn't spin true.
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Wednesday, March 29th, 2006 AT 7:27 PM
Tiny
PEPPERMRJ
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Both sides the same? Compare to a known good vehicle. I have seen bad halfshafts right out of the box.

Good luck and let us know. :)
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Wednesday, March 29th, 2006 AT 7:59 PM
Tiny
CBR74
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No, actually. Both sides wobble some, but the passenger side is significantly more pronounced. After a test drive on some twisties I've narrowed it down to the passenger side that's causing the woogie. It gets more pronounced as that side gets loaded, as in turning left and then fades away when turning right.

I'm now leaning away from the rotors being the problem since braking is strong and smooth at higher speeds. Only when it gets down to very slow speeds does it act like there's something amiss.
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Wednesday, March 29th, 2006 AT 8:23 PM
Tiny
PEPPERMRJ
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If you are not feeling the pulsation att he brake pedal I agree. :)
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Thursday, March 30th, 2006 AT 6:23 PM

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