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hope minis

clarksonclarkson Posts: 1,641
edited May 2008 in MTB workshop & tech
why is it that whenever i set them up on the workstand so that there is no or little drag, and the rotor is central to the pistons, they drag when i come back. or the rotor is no longer central? is it because they're new the whole system and the piston seals need to bed in? or is something broken? all the bolts are done up tight.

thanks for your help.
I said hit the brakes not the tree!!

2006 Specialized Enduro Expert
http://www.pinkbike.com/photo/3192886/

2008 Custom Merlin Malt 4
http://www.pinkbike.com/photo/2962222/

2008 GT Avalanche Expert
http://www.pinkbike.com/photo/3453980/

Posts

  • skylinerskyliner Posts: 613
    Do you loosen the PM bolts and pump the lever a few times before setting the rotor centrally between the pads and tightening the bolts?
    If not, give it a try.
    It's nice to be important, but it's more important to be nice.
  • ride_wheneverride_whenever Posts: 13,279
    you might want to take out and lube the pistons with dot 5.1 IIRC, as that is what is in the pistons.
  • skylinerskyliner Posts: 613
    Actually, Hope recommend lubing pistons with silicone lube as it doesn't evaporate and won't permeate through any holes in the backing plates and comtaminate the friction material.
    And you don't need to remove the pistons to do this, just pump them out a little and apply with a small brush.
    It's nice to be important, but it's more important to be nice.
  • ride_wheneverride_whenever Posts: 13,279
    Ooooooooooooo, that's good to know, would silicone high vacuum grease work, 'cos i have loads of that!
  • skylinerskyliner Posts: 613
    The electrical contact stuff from Maplin works, so maybe.
    It's nice to be important, but it's more important to be nice.
  • clarksonclarkson Posts: 1,641
    skyliner wrote:
    Do you loosen the PM bolts and pump the lever a few times before setting the rotor centrally between the pads and tightening the bolts?
    If not, give it a try.

    no i didnt. might give it a go. thanks!!
    I said hit the brakes not the tree!!

    2006 Specialized Enduro Expert
    http://www.pinkbike.com/photo/3192886/

    2008 Custom Merlin Malt 4
    http://www.pinkbike.com/photo/2962222/

    2008 GT Avalanche Expert
    http://www.pinkbike.com/photo/3453980/
  • FawdoFawdo Posts: 10
    Hi, my advise is to use copper slip on the pistons, it also stops the pads Squealing like a pig,

    Mini monos were a good upgrade and in general I like them but they don't have enough stopping power for a chunky monkey like me and I've had trouble with the res blowing a seal on the rear. (upgraded to larger disc but still not enough power!!!)
  • skylinerskyliner Posts: 613
    Copperslip can contaminate pads and piston seals too, which is why your brakes may not feel powerful enough. I've used Mono Mini's for DH with no problems @ 13.5st.
    It's nice to be important, but it's more important to be nice.
  • RockhopperRockhopper Posts: 503
    Red rubber grease for pistons and seals, coppa slip for the back of pads (although Hope say not to).
  • ThreeFishThreeFish Posts: 16
    skyliner wrote:
    Do you loosen the PM bolts and pump the lever a few times before setting the rotor centrally between the pads and tightening the bolts?

    You're greatly increasing the likelihood of sqeaks and squeals under braking if you set a caliper up this way. Chances are the lever feel will be soft and vague, too. Caliper pistons are designed to work symmetrically, so once the caliper has been centered over the rotor, then fit the pads and operate the lever to get the pistons out to a working position. If one piston is extending further/quicker than the other, push/pull the rotor against the side which is extending first and then gently pull the lever to extend the 'lazy' piston (you may find it easier to have somebody help out here, especially with an M4 or M6). You basically just need to manipulate the pistons until they both/all extend equally, thus making sure that the pads both hit the rotor at the same time (as their design intends). Symmetry is the key to a brake that performs well and feels good in your hand.
    Hopes can be a little fiddly to get set up, but it's worth spending a little time getting it right.
    You'll find caliper set-up videos in the Technical section of the Hope website, if you're interested.
    ***


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    '07 SX Trail
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