Help with brake work

Discussion in '6th Generation 2002-2013' started by AGuyWithABike, Feb 11, 2017.

  1. AGuyWithABike

    AGuyWithABike New Member

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    Hey guys and gals,

    Just a warning, I'm sure some of you will think i'm an idiot for even getting in this situation and considering some of these options.

    So I got a new set of front rotors as a gift from my parents that they ordered off of ebay. When I installed them the caliper and pads barely fit back over the rotors. When I tried to roll the bike the brakes stuck even before I pumped up the brakes again. My old rotors were 3.5mm thick and I measured the new ones at 4.5mm thick. The minimum thickness on the new rotors is stamped at 3.5mm so I was hoping to just have my honda dealer mechanic shave them down to 3.5mm but he said they won't do it for safety reasons, despite the manufacturer's minimum thickness stamp. The mechanic suggested I try some race spec pads as they would be thinner and might work.

    I would really like to avoid the hassle of trying to return the rotors to the ebay seller. My question for you guys is will race spec pads like EBC double H sintered pads actually be thinner than standard pads? If you don't think that would work, would you recommend taking the rotors to a brake shop to see if they would do it? Does anyone have experience with getting motorcycle rotors turned? I can't really afford a new set of OEM rotors due to the ridiculous price Any suggestions you have would be much appreciated, I'd like to have the bike ready for spring.

    Bike is a 2004 VFR800
     
  2. Hingley

    Hingley New Member

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    I don't blame the dealership for not wanting to shave your new rotors, bad idea
    My first guestion is what is the diameter of the new rotors compared to the old
    What is the offset of the old varies new rotors
    Are they the same?
    Now did you push the Calipers pistons back into the calipers before installing new pads
    If they did move back was it hard to do so?
    Is the calipers sliding on the calipers pins easily
    What I am getting is I would first make sure the calipers pistons are not sticking, if they are the calipers should be rebuilt
    If the new rotors are the exact same as the old rotors, except the thickness I would be very surprised if the problem is not some where's else.
     
  3. stoshmonster

    stoshmonster New Member

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    The 3.5mm thickness measurement refers to the minimum thickness that the rotors can be before they need to be replaced. Your new rotors at 4.5mm thickness are the correct starting thickness.

    As to the brake dragging issue.
    Did you remove the brake pads from your front calipers and thoroughly clean out all the brake dust and debris that was in the calipers?
    Did you thoroughly clean out all the brake dust that was around the dust seals on the pistons?
    Did you thoroughly clean all of the brake pad mounting components?
    Did you install a brand new set of brake pads in each front caliper? It's never a good idea to use old worn scored pads on new fresh rotors.
    Did you bleed out the old brake fluid from the reservoir,thoroughly clean the reservoir,and then put clean fresh brake fluid in?

    Before you installed the brake calipers did you push the pistons all the way back into the brake calipers?
    With the front wheel off the ground did you then gently pump the front brake lever until the brake pads touched the rotors?
    At that point did you spin the front wheel? A slight drag on the front wheel absolutely will be felt as the brake pads do not completely retract away from contact with the semi floating rotors.
     
  4. AGuyWithABike

    AGuyWithABike New Member

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    The new rotors are a full 1mm thicker than the old ones. I did indeed make sure to push the caliper pistons back in, and they weren't particularly hard to push. I'll take your advice and make sure to really clean the calipers thoroughly again before looking at other options. Any idea on the cost of a caliper rebuild? Thanks for the quick reply!
     
  5. AGuyWithABike

    AGuyWithABike New Member

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    I did not even think to pump the brake with the front still off of the ground, I'll give that a try. Thanks for the advice and for the quick reply. I love this forum you guys are super helpful.
     
  6. OZ VFR

    OZ VFR Member

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    I also bought a set of Chinese disks, and yes they are too thick to fit new pads.
    I flat sanded the new pads about 0.5.mm each to fix problem.
    But later got rid of said disks after I found a good second hand set really cheap.
    I also didn't like that they were much heavier than standard.
     
  7. stoshmonster

    stoshmonster New Member

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    Good on ya! Make sure those calipers are squeaky clean.

    A complete caliper rebuild isn't really necessary unless the pistons are badly scored and/or the piston seals are leaking. However keep in mind AGWAB that your bike is now 13 years old and piston dust seals and wiper rings don't last forever nor are they 100% effective at keeping dirt out of your brake system.

    Everytime you brake the pistons extend out of the caliper and brake dust and dirt gets deposited on the exposed piston surface. As the pistons retract back into the caliper microscopic bits of dust and dirt get drawn back into the caliper past the dust seals and wiper rings. That's called ingress dirt. Over time that dirt builds up inside your brake system,periodically it needs to be cleaned out.

    The reason I suggested that you clean out your front brake fluid reservoir is that there's a tiny return port in the reservoir body that can become clogged with that ingress dirt. If there's enough of a blockage in the orifice of that return port it can prevent the pistons from retracting back far enough away from the brake pads and cause excessive brake drag.

    Here's a link to a short vid where the guy is demonstrating the difference between floating rotors (which came stock on your '04) and full floating rotors. Turn up the volume and pay close attention when he spins the front wheel on the Aprilia RSV4. He gets roughly about a rotation and a half before the wheel stops turning and you can actually hear the brake pads dragging on the rotors. This is normal. This is exactly what you should see and hear with your front wheel off the ground.

    Get your front wheel up off the ground and squeeze your front brake lever until the pads make solid contact with the rotors,then release the front brake lever and perform the wheel rotation test.

    Click me.>>>https://www.youtube.com/embed/jJPCy2AsULo
     
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