Front brake rotor / hub runout
04-17-2011, 06:25 PM
#1
Front brake rotor / hub runout
Well after owning my 07 HR 350Z for 5 months, i've widdled my way thru things i didn't like about the car(stereo, shifter, lack of LSD).
Now i'm onto the recently discovered steering wheel shudder during high speed braking. Long story short the guy i bought the car from obviously curbed the front passenger corner (due to paint damage on bumper and fender arch).
Note: I will be making a DIY explaining this with pictures later this week.
Checking runout on the brake rotor I measured 0.015"
, acceptable is 0.0014"......
So to check things further i marked the high spot position on the rotor and hub, removed the rotor and got the hub runout of 0.005" aligning with my brake rotor high spot. There is no hub runout spec in the Nissan manual but do to the difference in radii this runout could easily magnify to the 0.015" seen at the rotor.
I then rotated the rotor 2 wheel studs (approx 180°) and remeasured. Got 0.015" runout aligning again with the hub high mark, not the rotor 1st measure mark.
This indicates the hub is tweaked thanks to previous owner's curb contact. $120 for a quality Timken replacement hub, and hopefully don't need to lathe the rotors.
Moral of the story: When testing a used car take it to a 100mph and slam on the brakes
Now i'm onto the recently discovered steering wheel shudder during high speed braking. Long story short the guy i bought the car from obviously curbed the front passenger corner (due to paint damage on bumper and fender arch).
Note: I will be making a DIY explaining this with pictures later this week.
Checking runout on the brake rotor I measured 0.015"
, acceptable is 0.0014"...... So to check things further i marked the high spot position on the rotor and hub, removed the rotor and got the hub runout of 0.005" aligning with my brake rotor high spot. There is no hub runout spec in the Nissan manual but do to the difference in radii this runout could easily magnify to the 0.015" seen at the rotor.
I then rotated the rotor 2 wheel studs (approx 180°) and remeasured. Got 0.015" runout aligning again with the hub high mark, not the rotor 1st measure mark.
This indicates the hub is tweaked thanks to previous owner's curb contact. $120 for a quality Timken replacement hub, and hopefully don't need to lathe the rotors.
Moral of the story: When testing a used car take it to a 100mph and slam on the brakes
Last edited by ian99rt; 04-17-2011 at 06:58 PM.
04-20-2011, 05:57 PM
#2
Well I didn't bother writing up a DIY as someone already has a Hub replacement instructions.
Either way heres a few pics and video of the runout measurement.
Replacement Timken hub came in, brought my brake rotor runout from .018" to less then .001".
Either way heres a few pics and video of the runout measurement.
Replacement Timken hub came in, brought my brake rotor runout from .018" to less then .001".
10-16-2011, 03:30 PM
#3
Figured i would update the thread for helpful info.
Even though the hub replacement cured the outside surface runout I still had brake shudder.
I again removed the rotor, flipped it backwards and bolted to the hub. Measured .022" of runout on the Inside surface while the outside was running true.
So new rotors and pads up front, problem solved.
Moral of the story, check brake runout on hub, outside, and inside rotor surfaces.
Even though the hub replacement cured the outside surface runout I still had brake shudder.
I again removed the rotor, flipped it backwards and bolted to the hub. Measured .022" of runout on the Inside surface while the outside was running true.
So new rotors and pads up front, problem solved.
Moral of the story, check brake runout on hub, outside, and inside rotor surfaces.
Last edited by ian99rt; 10-16-2011 at 03:48 PM.
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