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Thread: How much "pad drag" on front brake?

  1. #1
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    How much "pad drag" on front brake?

    I just replaced the front rotors on my 2007 Tuono Factory. Re used the pads, as they looked good with very little mileage on them.. Spinning the wheel afterwards, there seems to be a fair bit of drag as the pads are in contact with the rotors. Is there anything I should have / should not have done to reduce this? The calipers are typically dirty, but certainly not excessively so. Could they be "sticking" somehow? I did spin the wheel prior to reinstalling the calipers to check that the bearings were free, and all seemed normal, so it is brake drag. I haven't ridden the bike yet.

  2. #2
    apriliaforum prov-nov
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    did you check the fluid reservoir for some air space? If your new rotors are thicker than the old, and the fluid didn't have any space in the reservoir to occupy, you could get some drag as there is constant pressure being applied. just a thought.

  3. #3
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    Unlikely he'd have been able to slide the wheel on if the rotors were much thicker than the old ones.

    When the new rotors went on did they slide in easily without any binding or did you have to separate them? (the pads) If they didn't bind but did after a brake lever press and release then some grit could have gotten in and caused the pads to remain tighter against the rotor.

    That is why if you go through the trouble of replacing rotors, clean everything before disassembly and especially before just throwing new rotors on. Clean the calipers, inspect them, check the pads for grit waiting to score the new rotors etc. Don't half-ass anything to do with brakes, your life depends on doing it all properly.
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  4. #4
    apriliaforum expert cggunnersmate's Avatar
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    What discs did you replace with? OEM? OEM for your year/model? Do you have a service manual? Check specs, see what they are for your brake discs. Should at least have a minimum thickness Service Limit, hopefully max/min specs and check yours. Micrometer is best, calipers if that's all you have (cheaper but less accurate than a mic). Are your brakes properly bled? If the discs are in spec then it's likely a brake bleed issue.

    Light drag is normal, the pads should just lightly touch the discs with no pressure applied to the lever. Wheel should spin fairly freely but there should be some contact and a light scraping sound of the pads touching the discs.

    Also double check your wheel bearings make sure the drag isn't coming from them. And double check your torque on the axle nut and pinch bolts. If you over torqued the axle nut especially, may be squeezing the forks too much. Make sure you torqued those per the service manual procedure.
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    Thanks for the input everybody. I decided to take the calipers off again to look more closely at the pads. Brembo sintered pads; look to be fine. The rotors are new OEM from AF1 - SunStar. Looking more closely at everything, I think I may have a wheel bearing issue. If I turn the wheel slowly back and forth, there is a slight "groaning/squeeking" noise... this with the calipers off. The wheel turns smoothly other than this. More investigation required.....

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    Weird shit. The odd noise only happens when the front fender is on. For the life of me I can't figure out where its rubbing, but the noise is not from the wheel bearings, which seem perfectly ok. But the excessive drag is still there. I think the calipers must be sticking. Anybody rebuilt the Brembo 4 piston calipers?

  7. #7
    apriliaforum Member Kevlar's Avatar
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    Quote Originally Posted by YVRFACTORY View Post
    Thanks for the input everybody. I decided to take the calipers off again to look more closely at the pads. Brembo sintered pads; look to be fine. The rotors are new OEM from AF1 - SunStar. Looking more closely at everything, I think I may have a wheel bearing issue. If I turn the wheel slowly back and forth, there is a slight "groaning/squeeking" noise... this with the calipers off. The wheel turns smoothly other than this. More investigation required.....
    Well, SunStar doesn't make the best rotors, but Brembo does. I replaced a set of the former with the latter on the 05 TF=a little more pad drag until they bedded in, now fine. If you can spin the wheel with your hand, but hear a little noise, NBD (no big deal).
    Last edited by Kevlar; 08-03-2019 at 05:40 AM. Reason: NBD clarity
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  8. #8
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    clean the calipers with some mild degreaser & toothbrush til they are spotless.
    Rotate the pistons in the bores (if possible) Either use a piston plier or something
    that wont marr or leave witness marks.
    If there are retainer pins... remove clean & polish.
    Lastly scuff the pads with some 180 grit.
    Wipe the rotors down with brake cleaner on a lint free towel.
    A quick bleed is not a bad idea either.
    Use a q tip to lube the cleaned seals with some fresh brake fluid.
    You can exercise the caliper by putting a block/shim in so the pistons dont pop out.

  9. #9
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    Quote Originally Posted by turboblew View Post
    clean the calipers with some mild degreaser & toothbrush til they are spotless.
    Rotate the pistons in the bores (if possible) Either use a piston plier or something
    that wont marr or leave witness marks.
    If there are retainer pins... remove clean & polish.
    Lastly scuff the pads with some 180 grit.
    Wipe the rotors down with brake cleaner on a lint free towel.
    A quick bleed is not a bad idea either.
    Use a q tip to lube the cleaned seals with some fresh brake fluid.
    You can exercise the caliper by putting a block/shim in so the pistons dont pop out.
    Thanks, I've done all this and I believe all is well!

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