Shimming rotors
Thread Starter
Team Owner
Joined: Apr 2002
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From: All humans are vermin in the eyes of Guru VA
Cruise-In IV Veteran
Cruise-In V Veteran
Shimming rotors
So when we reinstall rotors, and shim them to eliminate runout. What do you use for shim stock?
Instructor
Joined: Apr 2007
Posts: 184
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From: Atlas is shrugging KC, MO area
Believe it or not, that's exactly what you use. You might have to search for it. It comes in packs of several pieces and are about 10" long. Check auto parts stores and machine shops.
Team Owner
Joined: Jul 1999
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From: Orange Park Florida
hehe, being a cheeeeep bastard.....aluminum foil....works fine....make sure you taper it off over several bolts.....say one bolt takes 2 thick, then either bolt on each side gets one thick....etc....
works fine for me....BTW, NAPA rotors on my front end are perfect right outta the box....the rears give the most troubles....
but they are not NAPA rotors....and the rotors are differant front to rear...
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
for aluminum foil, however many layers, I just knock a hole in it and put about an inch square over the stud or studs...depending...then bolt the rotor down with 3 bolts, leaving the two intermediate bolts off....between the 'high' side and the 'lo' side....so as not warp the rotor with force...maybe spring the metal, and my being cautious I don't wanna....
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Drifting
Joined: Oct 2004
Posts: 1,259
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From: Ontario
I used aluminum duct tape. It is a little thicker that foil but a lot stronger plus it is very nice to work with. I like to stick on the backside of the rotor then trim around the bolt holes with an razor blade. Like to above post said, taper it if you are using more than one layer.
Melting Slicks
Joined: May 2007
Posts: 3,246
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From: Bay Area CA
Stainless Steel Brake Corporation used to manufacture corvette disk shims in .004 to .015 tapered widths. SSBrakes.com. Part no. 1602 or a-1602, Doesn't show up on thier website, so you'll need to call them. 800-448-7722.
Last edited by RunningMan373; Jun 18, 2007 at 07:01 PM.
Burning Brakes
Joined: Nov 2001
Posts: 1,191
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I got some washer-like shims from McMaster-Carr too, I think - catalog is at home. I got the assorted sizes, and should last me quite long also. Takes forever - add shim, re-measure, change shim, re-measure, forget which side is high, forget where to put shim, measure again, add another shim......you get the picture. I tried to get it under .005"
Team Owner
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From: Reno Nevada
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Safety Car
Joined: May 2001
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From: Surrey
Yup, I've got Tanglefoot beer can behind mine (metal is 0.004" thick). Just used the kitchen scissors to cut 1"ish discs out of it & cut holes in the middle. Worked great & was a heck of a lot cheaper than I was quoted for some shim stock (plus it's a beautiful beer 
). If you get grief over blunting the kitchen scissors, just use them to cut a few sheets of emery/wet-or-dry & it'll bring back the edge. You'll need some abrasive to clean up the rust anyway. With 3 shims under one rotor & 2 under the other, I got runout well within spec.
). If you get grief over blunting the kitchen scissors, just use them to cut a few sheets of emery/wet-or-dry & it'll bring back the edge. You'll need some abrasive to clean up the rust anyway. With 3 shims under one rotor & 2 under the other, I got runout well within spec.
Melting Slicks
Joined: Mar 2004
Posts: 3,472
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From: Lake Ozark, MO
Been on the Forum for sometime and this is the first I've heard of shimming rotors...since I've put all new brakes on my 78 (still not driven)...can someone briefly explain what we're doing here.
Team Owner
Joined: Oct 2004
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From: Springfield MO
St. Jude Donor '07
Instructor
Joined: Apr 2007
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From: Atlas is shrugging KC, MO area
In a nutshell, excessive rotor runout will cause the calipers to pump air thereby causing spongy brakes.