Sure you don't mean .0035"?
Brake rotor questions
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,117
From: Crossville TN
You should be measuring the perpendicularity of the rotor face [to the spindle axis] for any "wobble" occurring in each revolution of the rotor. That measurement is termed "runout" by car guys...but it isn't actually a runout measurement. You should only have a few thousandths of an inch error in a surface true to that axis. Have the rotors been turned before? If they are really that cockeyed, I doubt they can be turned to "true" and still have adequate thickness.
Racer
Joined: May 2004
Posts: 343
Likes: 2
From: tampa fl
without a doubt it take a lot of work to remove the rotors. only a fool would go through that amount of labor to try and save a set of rusty old warped rotors.
dont be so cheap especially with your safety.
buy new ones.
dont be so cheap especially with your safety.
buy new ones.
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
There's a minimum thickness cast into the rotor. If it can be turned without going below that they are fine.
Many rotors now are very low quality (made in you-know-where). If you still have the factory rotors they are worth saving as long as they are above the minimum thickness.
Many rotors now are very low quality (made in you-know-where). If you still have the factory rotors they are worth saving as long as they are above the minimum thickness.
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Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
1.215 is the min. thickness.. Best to measure them first before turning. Edited.. I left out the 1! Sorry!
Last edited by Willcox Corvette; Jun 13, 2011 at 02:16 PM.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
This is the rear one (right). The left rear checked out fine. Both rotors were removed in the past (rivets were gone). Front ones still have the rivets. They look original.
Bearing play was setup, when rebuilding the trailing arms. Bearing play was .002" left, .003 right.
Going to check it again today and take a picture. The rotors look original. Min thickness on the face of the rotor is 1.215".
Hmm, maybe the rotor was mounted 180° off. Need to check that.
As far as price is concerned. When having to import heavy parts like brake rotors, these get pretty soon very expensive. And with that, i mean that i will probably pay double the price in the US due to transportcost, VAT, import,... So they easily turn to be a 400 $ thing. Not that I don't want to do that, it's just that probably runout will be something my new rotor will show also.
Bearing play was setup, when rebuilding the trailing arms. Bearing play was .002" left, .003 right.
Going to check it again today and take a picture. The rotors look original. Min thickness on the face of the rotor is 1.215".
Hmm, maybe the rotor was mounted 180° off. Need to check that.
As far as price is concerned. When having to import heavy parts like brake rotors, these get pretty soon very expensive. And with that, i mean that i will probably pay double the price in the US due to transportcost, VAT, import,... So they easily turn to be a 400 $ thing. Not that I don't want to do that, it's just that probably runout will be something my new rotor will show also.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Checked runout again after cleaning thoroughly the inside of the rotor : 0.021".
What do you think, replacing them or having them machined. I guess i will be replacing and going thru the shimming procedure. Sadly it's difficult to get the appropriate shims here.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Checked runout again after cleaning thoroughly the inside of the rotor : 0.021".
What do you think, replacing them or having them machined. I guess i will be replacing and going thru the shimming procedure. Sadly it's difficult to get the appropriate shims here.
What do you think, replacing them or having them machined. I guess i will be replacing and going thru the shimming procedure. Sadly it's difficult to get the appropriate shims here.
Considering the difficulty in getting rotors I would try to shim a .010 out rotor before buying a new one.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
And as always, the rotors must be turned while attached to the spindle. Machining them separately is a waste of time and material.Try indexing them first.
Melting Slicks
Joined: Apr 2008
Posts: 2,623
Likes: 242
From: Russell Ontario
St. Jude Donor '09
I have to disagree with my canadian friend, I have the original on my car and I had them turned on a good brake lathe and never had an issue , your rotors are not bad, just do a light cut and your good to go.Ron
Pro
Joined: May 2003
Posts: 593
Likes: 0
From: London England
I have to say I've never understood this idea of having rotors machined on the spindle.
If the spindle doesn't run true, either the bearings had it, the spindle is bent or the hub face isn't flat.
I'd much rather cure these issues and be able to have the rotors machined off the car. To me getting rotors machined on the spindle, or shimming the rotor is a bubba fix, sorry guys.
If the spindle doesn't run true, either the bearings had it, the spindle is bent or the hub face isn't flat.
I'd much rather cure these issues and be able to have the rotors machined off the car. To me getting rotors machined on the spindle, or shimming the rotor is a bubba fix, sorry guys.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,117
From: Crossville TN
The spindles aren't perfect...but they should be fairly true. If you get the rotors turned on a well set-up lathe, and you have "runout" in them when installed on the spindle...you need to check out the spindle. It gets checked out the same way (except you can really check runout and perpendicularity on it).
