are warped rotors visible?

I've been reading a bit about warped rotors, overtorqued lug nuts,
turning versus sanding rotors, and measuring the specs of the rotors'
thickness, etc.

OK, so I can put a tool on the rotors and check the size, but can I use
this tool to see if the rotor is warped?

I have a shimmy in the steering wheel when I brake. I also know that
the front bushings on the car are pretty well shot.

So, not knowing if my shim is from rotors or bushings, I'd like to try
and determine this. I have all of the replacement bushings, so I want
to replace these. Would it be practical to replace the bushings, then
clean/sand the rotors and replace the pads with OEM pads, clean
everything, and if it still shimmies, then just replace the rotors?

Any problems with trying new pads on the old rotors and just replace
them last if needed?

Thanks.

PS: forgot to add I should re-pack the wheel bearings.

 

In an earlier contribution to this discussion,

In order to check whether the discs (rotors) are running out (warped) you
need a dial indicator like http://tinyurl.com/lpy4r with a magnetic base to
attach it to a fixed part of the hub. The little plunger has to press
against the side of the disc. You then rotate the disc and, if there is any
lateral motion, the plunger moves in and out - causing the pointer to move.
You then need to compare the run-out with the maximum permitted amount, and
get the discs machined or repplaced if not within tolerance.
--
Cheers,
Roger
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Ingenious! There is a tool for everything - it seems. Unfortunately
we're expected to exchange currency for them.

;-(


Jamie

 

Or, just remove the tire and wheel, turn the rotor by hand and eyeball
it.

If it's warped, you'll see it.

 

yep... and you can rig up any old thing to get a pointer (pencil on top
of a jackstand, or whatever) up next to the rotor. Spin it 'til it
touches only at the highpoint, then rotate until the gaps the biggest
and slide a feeler gauge (or yardstick, depending on amount of warpage)
in there to measure the runout.

 

In an earlier contribution to this discussion,

I think you might just find something similar on sale in your part of the
world! <g>

--
Cheers,
Roger
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monitored.. Messages sent to it may not be read for several weeks.
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Nah. Consider the runout spec for the 700/900 series Volvos (I don't have
it off hand, but I'm pretty sure it's in the FAQ). Runout of a few
microns (warped rotor or just not mated properly to the hub) will cause
noticeable pedal vibration. Try eyeballing *that*.