The secret of getting new brake pads back on the rotor

Discussion in 'GS Boxers' started by Merlin III, Jul 19, 2013.

  1. Merlin III

    Merlin III Lone Wolf-No Club

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    Can anyone tell me what the secret is of getting the caliper with new brake pads back on the rotor?

    I decided to save some of my SS check and replace the rear pads on the 2001 1150GS with non-integral ABS brakes.

    I took the caliper off, took the old pads out, cleaned the insides of the caliper, put anti-seize lube where needed, compressed the pistons nearly all the way in, put the new pads on, opened the caliper as far as I could, and attempted numerous times to get the caliper over the rotor to no avail.

    It seems that the space between the pads is smaller than the width of the rotor. I looked up every thing I could find on the Internet and viewed Jim Von Baden's video where he does a brake bleed and in the process takes off and replaces the brakes. I also called the dealer to verify that they gave me the correct OEM pads. Thanks in advance for any responses.
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  2. JimVonBaden

    JimVonBaden "Cool" Aid!

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    Use a wide flat prybar between the pads. You do not have them spread quite far enough. With new pads you need them fully spread to get the caliper back on the rotor.

    Jim :brow
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  3. Emoto

    Emoto Sure, why not?

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    Also, check the level in the master cylinder after doing this. You may need to adjust it down if brake fluid was added as the old pads wore thinner.
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  4. Merlin III

    Merlin III Lone Wolf-No Club

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    Jim, I did that as you did in the video. Obviously, I can only estimate how much pressure you are applying, but I gave it nearly everything I had to the point of thinking about how much more pressure I could apply before the caliper would break :huh.

    One of the Internet articles mentioned leaving the pistons out a hair and I left it out about 1/16 of an inch before complete compression. Does that fact have anything to do with my problem? It wouldn't appear to me that it would since the piston side pad was well within the caliper shell. I finally reinstalled the worn pads and decided to take a couple of days away form this simple project and figure out why I was having this problem. I am not at the bike right now, but am thinking. How wide will the calipers open? As I recall, the only thing that is readily moveable are the pads and the pistons, right? Emoto,I did have to remove some fluid from the reservoir.
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  5. Dan-M

    Dan-M Long timer

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    What they said,
    Also, open the bleeder. Better to eject the old, dirty fluid than to push it back into the system. Especially with ABS.
    When you get the pistons fully in, close the bleeder immediately so you don't allow air in.
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  6. JimVonBaden

    JimVonBaden "Cool" Aid!

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    IF you got the right pads, and didn't install an aftermarket (thicker) rotor, then there is no reason you shouldn't be able to push the pads back with at least 1/8 inch of wiggle room to spare.

    Jim :brow
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  7. Merlin III

    Merlin III Lone Wolf-No Club

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    Okay, thanks. I will give it another try this weekend. Thanks.
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  8. Merlin III

    Merlin III Lone Wolf-No Club

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    Just to clarify a simple point (I hope), exactly what part of the caliper is it that I am attempting to spread? As I see it, the only moveable parts are the pistons, right? One article stated, as I understood it, that the pistons should only be compressed to within 1/8" of bottoming out. I definitely did that. Should I compress it more? I do see the potential of possible movement of the carrier by way of the booted carrier bolts, but I am not sure about that. Is there movement there that is in the spreading equation?

    I also had a PM recommendation that possibly I have a build up on the outside perimeter of the rotor that may need to be sanded off. I checked and there is some build up. As always, thanks for your input!
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  9. Jim Moore

    Jim Moore Long timer

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    Jam a big-ass flat head screwdriver in between the pads. Twist it to spread the pads apart. WAY the hell apart.

    You may need to open theh bleeder valve to let some fluid out after you do the first one.
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  10. slartidbartfast

    slartidbartfast Love those blue pipes

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    As others have stated, you should be able to get the pads far enough apart. I use a couple of tire levers or a really big screwdriver I ground/polished the sharp edges off. This is the time you should be flushing the old brake fluid out, especially as pushing the pistons all the way back will get some of the stale crud out of that cavity.

    Yes, the caliper slides on those rubber-booted pins. Now is also a good time to service those if it's not moving fairly freely. Unscrew the pins, clean, polish and lube with silicone grease (or whatever snake oil BMW suggests), making sure it can't get on the pads.
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  11. MIXR

    MIXR Been here awhile

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    Make sure the actual carrier is also moving (spreading). Sounds like you are only compressing the pistons, but not opening the actual carrier part? I've used really thick replacement pads and the caliper always opens up enough to feed the pads over the disk.

    Try this link: http://advwisdom.hogranch.com/Wisdom/BFDRear2.1.1.pdf
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  12. Steptoe

    Steptoe steptoe

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    The caliper is two seperate halves - You should be able to pull the sliding part of the caliper off/apart by hand.

    If you can't then the caliper has seized, and is why you can't fit it back in place with new pads fitted.
    #12
  13. Lat

    Lat Been here awhile

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    Leverage is a good thang! I would rather you use a tire tool with a spoon like shape or the ass end of an adjustable (Crescent type) wrench over a pointy "BASDriver" - to save the pad surface.

    I inherited a set on a bike with a loss of surface all the way to the back plate in the shape of a pointy screw driver on one pad. The noise and vibration the little captured floater pad surface generated was an annoying gremlin and hard to find - gone once I set the loose piece of pad free. Just hoping everyone benefits from that experience! ~Jeff
    #13
  14. Versys_User

    Versys_User Kingof9

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    Take your bike to a shop right now. :facepalm
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  15. Merlin III

    Merlin III Lone Wolf-No Club

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    Thank you everyone. I followed all the advice given and gave it one more try and I was successful. It was a leverage problem combined with a lack of experience with replacing disk brakes. Once I got it fully open I said to myself, "that was embarrassingly easy." :1drink

    I took it for a long test ride and everything seemed fine.
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  16. slartidbartfast

    slartidbartfast Love those blue pipes

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    Were both the original pads worn equally? If not, then even though you got it all back together, you have a problem there and should have serviced the caliper. If you don't know whether the brake fluid has been changed within the last two years, you should have done that at the same time too.
    #16
  17. Kyle B

    Kyle B "Dirty Jobs"

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    Just ride it! You have brakes? GOOD! Stay away from the dealer!
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