Infiniti: How to check brake rotor runout

Alora Duncan wrote:
 
http://www.nissaninfiniticlub.com/forums/showthread.php?s=014bf43d7210086a21cca509bc2a47c6& threadid=47476 

That should do it..


--

Steve

http://www.atlantaracing.com

"Alora Duncan" <com> wrote in message
news:google.com... 
http://www.nissaninfiniticlub.com/forums/showthread.php?s=014bf43d7210086a21cca509bc2a47c6& threadid=47476 

that'll work just fine.
 

That'll work fine too. I didn't see any wording about additional parts.

My dial gauge has a magnetic mount.

"Stephen Bigelow" <com> wrote in message
news:ZzTLb.62468$bloor.is.net.cable.rogers.com...
 
Like this.
http://store.yahoo.com/sjdiscounttools/fow72-520-199.html

FWIW,
you really don't need a rotor run out indicator/gauge,

if it vibrates when you step on the brakes you have excessive lateral runout
and the rotors need to be resurfaced





"Alora Duncan" <com> wrote in message
news:google.com... 
http://www.nissaninfiniticlub.com/forums/showthread.php?s=014bf43d7210086a21cca509bc2a47c6& threadid=47476 

"NissTech" wrote
 
runout 

Actually, you do. What you feel when you have pulsation at
the brake pedal is not lateral runout, it's thickness variation
at the rotor. Measuring a rotor for thickness variation is a
waste of time....as you mention....you can feel "that" on a
road test.

But you can't "feel" lateral runout if the rotor has no
thickness variation. So lets say you had a brake pulsation,
you machine the rotors....now we have no more thickness
variation. But, if you install the rotors and don't check
for lateral runout (which can be caused by rust on the
hub, lateral runout at the hub, etc.) then eventually, if
you do have lateral runout, you will end up with
thickness variation and a brake pulsation again.
Lateral runout will cause the rotor to hit the pads
ever so slightly as the rotor turns. This will eventually
cause thickness variation and a pulsation.

Which is why it's so important to clean the rust
and crap off at least the inside of the rotor surface
and the wheel hub surface that the rotor mates to.

Ian

> What you feel when you have pulsation at 

I don't currently feel pulsation when I *apply* the brakes; but
I do feel slight vibration in the steering at speed on smooth pavement.
I didn't relate the two (brakes & steering) as I am doing brakes
now (pads worn indicator just lit on my '90 Q45)... but may I ask
what the slight vibration in my steering is due to in a later thread.
 

Does this only apply if the rotors are REMOVED from the car?

I don't plan on removing the rotors (unless I have to) and I've
never done that. I suspect I'd have to remove the rotor if the
brake rotor thickness isn't up to spec or if the rotor lateral
runout is too great or if the rotor is badly grooved. Yes?

"Alora Duncan" wrote
 

Yes.

Ian

> I didn't see any wording about additional parts.

It may be more obvious to you (i.e., more experienced than I am); but,
I've never done a brake job before so I'm more unsure of myself.

From this web page:
http://www.sjdiscounttools.com/cen-6450.html
The wording (verbatim) which I'm worried about is:
• With optional attachments check tire and wheel run-out

(BTW, those SAME description used to be on the description for the 3D103
yesterday, and I wrote to the web site, which they seem to have
corrected between yesterday & today so those words only seem to
show up on the #6450 today).

I guess if "brake run-out" is a different test than "tire & wheel run-out"
(aren't the tires & wheel mounted to the rotor?) then I'm not worried I'll
need more equipment.

Still, that $132.25 tool (#6450) seems indistinguishable (to me, from
the picture anyway) from the $75.16 ($3D103) tool I actually ordered:
http://www.sjdiscounttools.com/sto3d103.html

On a different note, I LIKE you other astute suggestion for run-out tests: 

What I like about this idea is the magnetic mount is 1/3 cheaper than
the flex-arm dial-gage mount and it seems to be more generally adaptable
(is it?) than the vise-grip flex-arm mount (which is better?).

But, uh, oh, again, the ambiguity of it all. Notice these two photos:
http://store.yahoo.com/sjdiscounttools/fow72-520-199.html
http://store.yahoo.com/sjdiscounttools/fow72-641-300.html
Which one would you buy? The first is $43.87. The second is $105.27
The only difference I see is the arm off the magnet is either flexible
(in the more expensive case) or rigid (in the much less expensive case).

The description for the first #FOW72-520-199 (43.87 dollar tool) says:
FOWLER & NSK 72-520-199 - DIAL INDICATOR 0-1IN
MAG BASE 0-100 CONTINUOUS READING
Indicator features:
• 1" travel - continuous reading
• AGD group 2; 2-1/4" dial diameter
• Revolution counter
• Lug back mount
Magnetic base features:
• 85 lb. pull strength
• On/off switch
• Fine adjustment

While the description for the double-the-price (#FOW72-641-300) tool says:
FOWLER & NSK 72-641-300 - DIAL-IND 0-1/FLEX-ARM/MAG-BASE
# Multipurpose tool with 12-1/2" flexible arm
which can be set in any desired plane.
# Great for precision measurements on engines
# Dial Indicator measures 0-1" in .001" graduations
# Includes: Gage, contact tip, locking flexible arm
and On/Off magnetic base. Package in fitted case.

QUESTION: Would you buy the rigid arm mount or double-the-price flex arm?
(which is better, all around, for jobs, including brake rotor run out)?

Alora Duncan
com