Howdy,
This doesn't address the "downhill" part. That seems pretty crazy.
That said... When you replace your pads / rotors, tighten the rotor to the
hub and check the hub itself for both runout and play. We recently had an
'06 Civic that either had its hub bent during a wheel bearing replacement
or via a pothole and it wasn't obvious what was wrong until someone made
that very simple check.
You don't even have to have real tools to do this, thought it obviously
wouldn't hurt. Just tighten the rotor to the hub and rig up an indicator
out of anything that's sitting on the ground with a part close to the edge
of the rotor and spin the rotor. Your eye will do a good job of seeing
very small runout like this, or you can get it close enough that it'll
scrape on the high points.
A good shoptalk lister would use this as a reason to go buy a magnetic
base / flexible arm / dial indicator though. :-)
Mark
On Mon, 20 Jun 2011, jibjib at att.net wrote:
> I have an interesting issue puzzling me. My 2006 Chevy Malibu is about
> ready for brakes, which I will be doing shortly. The biggest issue is a
> pulsing from the left front wheel. The pulsing is very mild for all
> driving, almost indiscernible. When I am driving down hills, even when the
> brakes are dead cold, the vibration has gotten moderately severe; to the
> point that I'm thinking it might be more than just the rotor. I did the tie
> rod ends at 78k miles and now we are at 118K.
>
>
>
> The shimmy has always been worse on down hills, which perplexes me.
>
>
>
> The car will be getting new rotors and brake pads up front, where the shimmy
> is. If there is still a problem, that I do not see when I change out the
> rotors and pads, I'll address it, but I was just wondering if anyone had a
> plausible explanation of why the shimmy is so much worse on a downhill. It
> is not heat build up, as I've experimented with not using the brakes until
> the downhill and from the first application, the shimmy is far worse.
>
>
>
> Thoughts?
>
> Thanks in advance,
>
>
>
> Jack
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