02-23-2014, 10:17 AM | #1 |
Drives: '12 2LT Convertible Join Date: Mar 2012
Location: Belmont, California
Posts: 1,701
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Caliper / Rotor Alignment Question
Update: Problem solved. See post #11 below.
A few months back I upgraded my 2LT to Brembos (AKA SS brake conversion). I bought the calipers from a member here and had Mike (great guy) powder coat them. They were rebuilt with new bleed valves, cross over tubes, cylinders, seals and dust boots. The front calipers were also rethreaded with Time-Cert inserts after Mike found the originals had some stripped threads. I bought other parts (pins, Goodridge lines and Hawk HPS pads) and a set of SS DBA rotors from Sleez (great guy). DBA part #s: 42604SL (LH front, slotted) 42604SR (RH front, slotted) 42605SL (LH rear, slotted) 42605SR (RH rear slotted) Hawk Part #s: HB194F.570 rear HB453F.585 front I bought the caliper bolts and SS dust shields from the dealer. All parts were installed by an ASE certified mechanic with me as manual labor. The car stops fine and does not pull left or right. After the upgrade I noticed a slight clicking sound when I am above say 20 MPH. It comes and goes. I hear it most when driving next to walls. I've read this can be a consequence of slotted rotors. So I somewhat accepted it. Recently I have noticed my right front wheel has more brake dust when washing than does the left. So yesterday I decided to do some investigating. I jacked the front end up and rotated the wheels manually. I could hear the brakes rubbing a bit. The wheels stopped spinning fairly quickly (approx. 2-3 rotations on a full strength spin). I pulled the front wheels and did a thorough inspection. What I found is that the rotors are not completely centered in the calipers. Each is off by about 2-3mm. You can see this in the attached pics. Note the difference between the caliper half junctions and the rotor centerlines. At installation time I did note that it was a bit harder to insert the inner pad on each front wheel. I didn't think much of it. I figured it was just new brake pads. Each caliper is completely flush with the mount point and the caliper bolts are in per torque spec. So the question is: "Is this normal?" If not, then it seems the DBA rotor "hat" is a bit too tall because for a perfectly centered rotor, the rotor would need to come out an additional 2-3mm. Do rotor spacers exist? If I could move the DBA rotors 2-3mm away from the hub, then they would be centered in the caliper. I believe I have more than enough length on the wheel bolts to accommodate this rotor "extension". Would this cause me any grief if I later upgrade to aftermarket wheels? I have not yet inspected the rear caliper/rotors. Maybe today. Thoughts? Suggestions? Thanks in advance!
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Mods: GM Locking Gas Cap, RS License Plate Frame, SS Brembos, ZL1 FrontEnd, 14/15 Convertible Top
Last edited by intensifi; 03-04-2014 at 07:05 PM. |
02-23-2014, 12:26 PM | #2 |
Drives: 2010, 2LT, RS, 6M, ABM (#1893) SOLD Join Date: Mar 2011
Location: Willits, CA
Posts: 1,437
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typically the calipers may need to be shimmed to center the CALIPER to the rotor.
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2010 2LT/RS; 6M, ABM, Torq Thrust M w/custom center caps, Solo MachX-LLT, Blue Anodized Pedals, Barton Shifter w/UMI blue anodized pistol grip, Ported IM from Mace, 25mm isolator/spacer from Mace, Vararam CAI, Euro Rear Fascia, RX Breather Cap. SOLD 4/23/13.
Now have a 1965 Chevelle 4 dr wagon!! |
02-23-2014, 01:02 PM | #3 | |
Drives: '12 2LT Convertible Join Date: Mar 2012
Location: Belmont, California
Posts: 1,701
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Quote:
I may be missing something but if a shim was put in between the caliper and the mount point (knuckle?) then the problem would become worse as the caliper would move further "out" (i.e. away from the centerline of the rotor). This would give more space for the outer pad, but even less for the inner pad. The issue appears to be the inner pad doesn't have as much space as the outer pad. On the outer pad I can see the tops of the cylinders pushing against the back of the pad. On the inner side, I can't even see the cylinder tops.
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Mods: GM Locking Gas Cap, RS License Plate Frame, SS Brembos, ZL1 FrontEnd, 14/15 Convertible Top
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02-23-2014, 02:01 PM | #4 | |
Drives: 2010, 2LT, RS, 6M, ABM (#1893) SOLD Join Date: Mar 2011
Location: Willits, CA
Posts: 1,437
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Quote:
to check the center of the caliper to the rotor, disregard the pads/pistons, check the caliper itself with the pads removed to see if it's centered, if it is, then you have an internal caliper issue. it should be pretty difficult to have one side to have more throw than the other.
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2010 2LT/RS; 6M, ABM, Torq Thrust M w/custom center caps, Solo MachX-LLT, Blue Anodized Pedals, Barton Shifter w/UMI blue anodized pistol grip, Ported IM from Mace, 25mm isolator/spacer from Mace, Vararam CAI, Euro Rear Fascia, RX Breather Cap. SOLD 4/23/13.
Now have a 1965 Chevelle 4 dr wagon!! |
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02-23-2014, 07:52 PM | #5 | |
Drives: '12 2LT Convertible Join Date: Mar 2012
Location: Belmont, California
Posts: 1,701
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Quote:
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Mods: GM Locking Gas Cap, RS License Plate Frame, SS Brembos, ZL1 FrontEnd, 14/15 Convertible Top
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02-23-2014, 08:25 PM | #6 |
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I think it's a caliper mounting problem, not a rotor issue. How thick is the powder coating on the calipers? Are the threaded inserts installed correctly? Looks like something is pushing the calipers outward, unless the rotor hat is wrong, which is unlikely. Pull the front calipers and knock the powder coating off the mounting ears and make sure the thread inserts are installed flush.
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ProCharger P1X, Vengeance Racing Kaotic Cam, ARH Headers and Exhaust with Borla ATAK mufflers, MGW Shifter, MTI Drop Springs, Forgeline RB3C Wheels, 3.91 gears, Night Owl LED Control System
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02-23-2014, 08:35 PM | #7 |
Drives: 2005 Corvette Join Date: Nov 2009
Location: Loganville, GA
Posts: 712
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There is no powdercoating on the mounting ears, that was totally masked and the timecert inserts are fully seated. The best way to check would be to get a stock rotor and see how that aligns. barring that, I think if you could find some thin washer shims, you could put them on the wheel studs behind the rotors to push the rotors out a little bit and align them that way.
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02-23-2014, 11:30 PM | #8 | |
Dimitri
Drives: 68 GTO 455 Ram Air; 2014 Camaro ZL1 Join Date: Jan 2014
Location: Novato, California
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02-24-2014, 12:10 AM | #9 | ||
Drives: '12 2LT Convertible Join Date: Mar 2012
Location: Belmont, California
Posts: 1,701
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Quote:
I have the stock SS rotors that I didn't end up using. My plan for next weekend is to get some more caliper bolts and then remove the front DBA rotors and compare them with the stock rotors. My plan is first to compare overall height. If they are the same then I'll compare the thickness of the top of the hat. If the DBA rotors are the same as the stock SS rotors... Quote:
To be clear though. This situation is not normal, correct?
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Mods: GM Locking Gas Cap, RS License Plate Frame, SS Brembos, ZL1 FrontEnd, 14/15 Convertible Top
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02-24-2014, 01:47 PM | #10 |
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It's not normal for sure. If the calipers are fully seated against the knuckle, just compare your rotor to a stock one. I checked the P/N of the hub and knuckle for a V6 and V8 car just to be sure, and there the same, like I thought they were. I'm not a fan of spacing the rotor away from the hub, unless you can find a full shim that will entirely support the rotor, and I have never seen one nor know of one. I wouldn't use washers. Something is causing this. Just need to find out what and remedy it. Just might be the new rotor hat. Not much else it could be.
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03-04-2014, 11:31 AM | #11 |
Drives: '12 2LT Convertible Join Date: Mar 2012
Location: Belmont, California
Posts: 1,701
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Update:
Last weekend I had time to remove the wheels and work on the front calipers. It turns out there is nothing wrong with the DBA rotors. They are almost an exact match for the stock SS rotors. The mis-alignment was from a combination of two factors: 1) There was a small amount of yellow Loctite left on the knuckle from the previous v6 caliper bolts. As the new bolts tightened the residue was enough to force the caliper slightly out of alignment. I could make excuses that it was getting dark when we got around to installing the new calipers initially, but that is still my fault. I'm saying it is from the previous V6 caliper bolts because I remember those bolts using yellow Loctite. 2) The Time-Cert insert tops are ever so slightly below (~.25mm) the level of the rest of the caliper ear. In addition the inserts are ever so slightly smaller (~.25mm) than the enlarged ear bore to accommodate the insert. What was happening was that the new red Loctite on the caliper bolt was separating from the bolt and pushing out of the gap between caliper and the knuckle created by the insert. I noticed this as I was tightening the new bolts. Seeing those Loctite shavings didn't look right. So I removed the bolts, cleaned out the shavings (note there was still plenty of Loctite on the bolts) and reinserted the bolts. Problem solved. No clicking anymore. So SSMickey was right, just for a different cause. Loctite was the culprit, not powder coat.
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Mods: GM Locking Gas Cap, RS License Plate Frame, SS Brembos, ZL1 FrontEnd, 14/15 Convertible Top
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03-04-2014, 02:03 PM | #12 |
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Loctite...who'd of figured that. Glad you got it figured out and let everyone know. Just might save somebody else a headache.
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ProCharger P1X, Vengeance Racing Kaotic Cam, ARH Headers and Exhaust with Borla ATAK mufflers, MGW Shifter, MTI Drop Springs, Forgeline RB3C Wheels, 3.91 gears, Night Owl LED Control System
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03-04-2014, 04:59 PM | #13 |
Drives: 2005 Corvette Join Date: Nov 2009
Location: Loganville, GA
Posts: 712
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glad you fixed it!
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03-04-2014, 11:33 PM | #14 |
Drives: 2010, 2LT, RS, 6M, ABM (#1893) SOLD Join Date: Mar 2011
Location: Willits, CA
Posts: 1,437
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glad it was an easy fix, loctite in moderation!!
one thing i have seen a lot in wrenching, very little loctite is actually needed to do the job. chalk it up to a learning moment! good job!
__________________
2010 2LT/RS; 6M, ABM, Torq Thrust M w/custom center caps, Solo MachX-LLT, Blue Anodized Pedals, Barton Shifter w/UMI blue anodized pistol grip, Ported IM from Mace, 25mm isolator/spacer from Mace, Vararam CAI, Euro Rear Fascia, RX Breather Cap. SOLD 4/23/13.
Now have a 1965 Chevelle 4 dr wagon!! |
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