Disc Rotor Runout
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Disc Rotor Runout
Tried unsuccessfully to post this in Off Topic.
How does one determine what is acceptable disc rotor runout; how many thousandths is acceptable?
I purchased a dial runout gauge and would like to use it but don't know how much runout is OK and how much is bad?
Where does one find such specs?
Thank you,
Kurt
How does one determine what is acceptable disc rotor runout; how many thousandths is acceptable?
I purchased a dial runout gauge and would like to use it but don't know how much runout is OK and how much is bad?
Where does one find such specs?
Thank you,
Kurt
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Gordonm,
Thank you.
Is this a standard rule of thumb or does it vary for vehicles?
Would this be the same tolerance for my minivan or my wife's Audi, in other words for all rotors for all cars or is there some place to find specific tolerances by vehicle manufacturer?
Thank you.
Is this a standard rule of thumb or does it vary for vehicles?
Would this be the same tolerance for my minivan or my wife's Audi, in other words for all rotors for all cars or is there some place to find specific tolerances by vehicle manufacturer?
Premium Supporting Vendor
Joined: Nov 2002
Posts: 1,485
Likes: 81
From: Santo TX
According to the factory service manual total runout should not exceed .002" but that is with the wheel bearings snugged so there is no play. You wouldn't drive it with the bearings set like that but that is what the shop manual says for checking the runout. This measurement is for non-floating calipers. There is a bit more leeway for floating calipers.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
No, rotor runout is not critical on cars with floating calipers.
If you can't feel vibration in the brake pedal or shaking in the steering wheel, don't worry about it.
Drifting
Joined: Sep 1999
Posts: 1,970
Likes: 91
Tried unsuccessfully to post this in Off Topic.
How does one determine what is acceptable disc rotor runout; how many thousandths is acceptable?
I purchased a dial runout gauge and would like to use it but don't know how much runout is OK and how much is bad?
Where does one find such specs?
Thank you,
Kurt
How does one determine what is acceptable disc rotor runout; how many thousandths is acceptable?
I purchased a dial runout gauge and would like to use it but don't know how much runout is OK and how much is bad?
Where does one find such specs?
Thank you,
Kurt
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Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Stainless calipers filled with O ring pistons stockish pads....
make sure the rear hubs are well within specs...very snug...
front too, for that matter...new rubber and maybe steel lines....
fresh master cylinder....and watch for anything even remotely looking like a leak out of that proportioning valve..be very aware, it's a sneaky SOB out of that light switch in that brass block....the the final modification that stands your shark on the nose every time and makes the pedal solid as a rock....
HYDROBOOST apparently the best/easiest is from a Astro van....THAT is the final thing I did to finally fix my brakes after covering all the other bases.....brakes that WORK, and any vacuum assist stockish boosters are CRAP, and that is across the lines from any car/maker....
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
I used some shim stock and siccors and cut out some "washers" and sandwiched them between the rotor and hub. I also painted 1 of the studs and the corresponding hole in the rotor so I would know the orientation if I remove the rotor.
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Gary,
At the risk of sounding dumb, how do I measure/set the end play of the bearing?
I always just tightened them by hand until they were snug and the cotter pin hole lined up
Kurt
At the risk of sounding dumb, how do I measure/set the end play of the bearing?
I always just tightened them by hand until they were snug and the cotter pin hole lined up
Kurt
Tech Contributor
Joined: Aug 1999
Posts: 15,131
Likes: 3,938
From: Connecticut, USA
The rear require rebuilding and machine work, the fronts may just need to dress the nut.
