Caliper pins hitting rotor !!
08-22-2010, 07:20 PM
#1
Team Owner
Thread Starter
Caliper pins hitting rotor !!
Well here is what I found:
These are new in box DBA that I bought from a forum member. This is the second track day on them. When I looked at the spacing between the rotor face and the pin face I found it to vary greatly. Mostly some of the outer pins looked to be touching. and the corresponding pin on other side of the rotor had a significant gap. The blurred picture shows this gap, if you look closely you can see the head of the pin and a good amount of space to the rotor. The corresponding pin, as shown looked to be in contact with the rotor.
When I put the stock rotors back on there were no pins close to the rotor face. In fairness, this is a used rotor (seen a few track days) so may be an equally worn DBA would look the same. But it clearly looked more evenly spaced between the pins.
Looking at the rotor face you can clearly see some pins must be contacting. The size of the burnished area is identical to the diameter to the pin and seems to be where the pins would hit, I believe. Both rotors showed this same pattern on
both sides of the rotor although not equally. The wear is much worse on the outside rotor face. On the close up you can see the rotor face looks great except for the web cracking in the burnished area.
The used rotors that I took off before installing these show no evidence of this pin burnishing.
I have had no unusual noise that would be associated with the hubs. I did try and see if there was any play in the wheel. Holding the wheel at 12 and 6 position it was like a rock. Holding at the 3 and 9 position I seemed to get some movement but I was told that it might be play in the steering.
AND: I checked the date stamp and they are from 2007 !!!! Was there any issues with that year??? I didn't know these were around that long ......
How much can you grind the pin face down? It seems like the pin face is shaped. Does the pin actually keep the rotor from flexing or aid in run out in some manner??
I don't think I'm too comfortable running these DBA's and may buy some new OEM's
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DH
These are new in box DBA that I bought from a forum member. This is the second track day on them. When I looked at the spacing between the rotor face and the pin face I found it to vary greatly. Mostly some of the outer pins looked to be touching. and the corresponding pin on other side of the rotor had a significant gap. The blurred picture shows this gap, if you look closely you can see the head of the pin and a good amount of space to the rotor. The corresponding pin, as shown looked to be in contact with the rotor.
When I put the stock rotors back on there were no pins close to the rotor face. In fairness, this is a used rotor (seen a few track days) so may be an equally worn DBA would look the same. But it clearly looked more evenly spaced between the pins.
Looking at the rotor face you can clearly see some pins must be contacting. The size of the burnished area is identical to the diameter to the pin and seems to be where the pins would hit, I believe. Both rotors showed this same pattern on
both sides of the rotor although not equally. The wear is much worse on the outside rotor face. On the close up you can see the rotor face looks great except for the web cracking in the burnished area.
The used rotors that I took off before installing these show no evidence of this pin burnishing.
I have had no unusual noise that would be associated with the hubs. I did try and see if there was any play in the wheel. Holding the wheel at 12 and 6 position it was like a rock. Holding at the 3 and 9 position I seemed to get some movement but I was told that it might be play in the steering.
AND: I checked the date stamp and they are from 2007 !!!! Was there any issues with that year??? I didn't know these were around that long ......
How much can you grind the pin face down? It seems like the pin face is shaped. Does the pin actually keep the rotor from flexing or aid in run out in some manner??
I don't think I'm too comfortable running these DBA's and may buy some new OEM's
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[/IMG]DH
08-22-2010, 08:53 PM
#3
Team Owner
Thread Starter
I don't have a measuring device or a set of new OEM to compare to. So the used OEM I have may seem to fit with plenty of pin clearance because they are worn.
Would bad wheel bearing cause this wear???
DH
08-22-2010, 10:24 PM
#4
Drifting
Member Since: Feb 2005
Location: in ur mirror, 'bout to pass.. CA
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Well shoot, slap a ruler on the edge of 'em and read the little fractions on the stick! Can't be that hard... From that closeup it sure does look as if the DBA's are thicker.
08-22-2010, 10:32 PM
#5
Race Director
rotors are slightly off center, RB had the same problem. There was another post just like this last week. Either trim the pins or shim the caliper out.
08-22-2010, 10:33 PM
#6
Race Director
btw, if you have spindle ducts, or have modified the plate that holds the ABS wire, that will also change the centerline between the caliper and rotor. A thicker aluminum spindle duct will push the rotor outward relative to the caliper.
08-22-2010, 10:43 PM
#7
Team Owner
Thread Starter
DH
08-22-2010, 10:48 PM
#8
Team Owner
Thread Starter
No I am completely stock ... except for the DBA and Hawk HP Plus pads and Dot 4 fluid.
Still seems not to make sense though. If offset is wrong I would think there would be no pins touching on on side or the other. But mine are.
Can you please tell me how to check my hubs. If my hubs are failing would you expect to see the pins hitting the rotor face?
How much can you safely shave off the pin end .................
DH
08-23-2010, 10:02 AM
#9
Le Mans Master
Bottom line is that aftermarket does not have the same tolerence as OEM. Any time you use aftermarket you can run into these issues. I would imagine the heat generated by those pins rubbing is not good for the caliper and the fluid inside. I'd switch back to OEM. The price is better and they will last just as long.
08-23-2010, 11:18 AM
#10
Safety Car
Bottom line is that aftermarket does not have the same tolerence as OEM. Any time you use aftermarket you can run into these issues. I would imagine the heat generated by those pins rubbing is not good for the caliper and the fluid inside. I'd switch back to OEM. The price is better and they will last just as long.
08-23-2010, 03:35 PM
#11
Drifting
Member Since: Feb 2005
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If the DBA's were designed to be OEM replacement rotors for C5/C6, then why would the offset be different? Are the C6 Z06 rotors a different offset? I know the stock C6's fit just fine; it's what I'm running currently.
Curiouser and curiouser....?
Curiouser and curiouser....?
08-23-2010, 04:30 PM
#12
Team Owner
Thread Starter
Bottom line is that aftermarket does not have the same tolerence as OEM. Any time you use aftermarket you can run into these issues. I would imagine the heat generated by those pins rubbing is not good for the caliper and the fluid inside. I'd switch back to OEM. The price is better and they will last just as long.
But I already have checked with RichieRich (Forum Vendor) a for new fronts.
Have a track day in 4 weeks so there is time to figure this out.
Has anyone actually ground their pin tips down. How much can you safely remove ???
DH
08-23-2010, 04:38 PM
#13
Le Mans Master
And I know another hundred that don't. I have been doing this for a decade and have bought tens of thousands of dollars in aftermarket parts and have had all kinds of experiences. My point is that when you buy aftermarket, anything is possible. They are making parts for dozens if not hundreds of cars. I never had a problem with an OEM part fitting correctly, but have had lots of problems with aftermarket parts, even ones that are twice the OEM part.
08-23-2010, 04:39 PM
#14
Le Mans Master
Well I'm waiting to hear from DBA and more knowledge from you guys.
But I already have checked with RichieRich (Forum Vendor) a for new fronts.
Have a track day in 4 weeks so there is time to figure this out.
Has anyone actually ground their pin tips down. How much can you safely remove ???
DH
But I already have checked with RichieRich (Forum Vendor) a for new fronts.
Have a track day in 4 weeks so there is time to figure this out.
Has anyone actually ground their pin tips down. How much can you safely remove ???
DH
08-23-2010, 05:01 PM
#15
Team Owner
Thread Starter
DH
08-23-2010, 05:13 PM
#16
Race Director
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In a slightly different vein, I bought the two piece DBA for C5 and found way too much interference with hat bolts hitting the caliper/bracket. Had to send them back to Tirerack. They first wanted me to send them pictures etc. even though my explanation of the @#$% bolts were sticking out too long on the hat should have been good enough for them. First problem I have had with Tirerack but I expect them to know the application validity since they sell 'em.
08-23-2010, 05:49 PM
#18
Team Owner
Thread Starter
08-23-2010, 06:10 PM
#19
Supporting Vendor
In a slightly different vein, I bought the two piece DBA for C5 and found way too much interference with hat bolts hitting the caliper/bracket. Had to send them back to Tirerack. They first wanted me to send them pictures etc. even though my explanation of the @#$% bolts were sticking out too long on the hat should have been good enough for them. First problem I have had with Tirerack but I expect them to know the application validity since they sell 'em.
They since modified the design and went to a recessed fastener.
-Ken
08-23-2010, 06:33 PM
#20
Team Owner
Thread Starter