Formula Oro - piston(s) not retracting

PJPenrouz
PJPenrouz Posts: 136
edited June 2009 in MTB workshop & tech
I've had my F ORO K18 brakes for about a year and particularly on the front one the pistons are not retracting properly which causes this very annoying noisy rubbing, especially after the brake application. I think this could be due to corrosion but not sure about it. Could this be adjusted? Or do I need to replace any parts?
Cheers

Comments

  • nicklouse
    nicklouse Posts: 50,673
    have you cleaned the pistons?


    brake do need some looking after.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • PJPenrouz
    PJPenrouz Posts: 136
    Yes I did - with isopropyl alcohol. Do I need new pistons then?
  • nicklouse
    nicklouse Posts: 50,673
    nope just more cleaning an lubing until the both move the same.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • PJPenrouz
    PJPenrouz Posts: 136
    OK, what's the best way to clean the brakes? I got new pads and cannot push the pistons back enough to even put the wheels back on. I used the old pads and a screwdriver to press the pistons back, but they won't go far enough. I tried to clean the pistons but access is limited. Any good method how to do that?
    Cheers
  • GMARS70970
    GMARS70970 Posts: 71
    If you push the brake lever forwards does the rubbing noise stop? Is the lever returning to its original position after use?

    I had this problem with my Formula Oro brakes. When I pulled the brake lever the brakes stopped perfectly, they just didn't release properly.So it either stuck on or gave the rubbing noise your getting.

    After bleeding the brakes & changing the brake lever piston I found that the pivot point that the screwed push rod goes through was siezed! :oops: :oops:

    I pushed out the alloy pivot, removed the plastic sleeve & the alloy part had started to corrode & swelled in size. I cleaned the alloy part with wet-n-dry paper, re-greased both parts & re-fitted.
    Works perfectly, better than it ever did. So i've done the same to the back brake & its perfect now also. :D:D
  • PJPenrouz
    PJPenrouz Posts: 136
    Yes, the levers return OK. I think the problem is around the pistons.
  • nferrar
    nferrar Posts: 2,511
    Just got a bike with K18's on to, first proper ride was the Merida 50k last Sunday and went down to the metal on the pads front and rear, the levers also started returning much slower. Spent some time last night cleaning the pistons with isopropyl then lubing with a bit of dot fluid, they seem better now but still not as snappy as when new so will prob have another go tonight. How far can you afford to let the pistons extend out and not bugger them up and need to bleed the brakes?
    Also is it me or is the circlip used on the pad retainer a nightmare to get off? Wouldn't fancy doing that on the side of a trail if trying to change pads.
  • nicklouse
    nicklouse Posts: 50,673
    PJPenrouz wrote:
    Yes, the levers return OK. I think the problem is around the pistons.

    sounds like the brakes were bled with the pistons not pressed home. Too much fluid in the system.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Father Faff
    Father Faff Posts: 1,176
    I 've got a 2007 Meta 5 with K18 brakes and both brakes had problems which turned out to be a known manufacturing defect with the Formula importers sorted out, however it took them an age to do. In the meantime my LBS lent me some extrmeely powerful Maguras which were great!
    Commencal Meta 5.5.1
    Scott CR1
  • Dazzza
    Dazzza Posts: 2,364
    nicklouse wrote:
    PJPenrouz wrote:
    Yes, the levers return OK. I think the problem is around the pistons.

    sounds like the brakes were bled with the pistons not pressed home. Too much fluid in the system.

    Not only that but when you bleed you're meant to hold the levers in until it's all finished id imagine it's done to help the pistons retract.

    I've certainly had no problems when bleeding you soon learn how to do it properly or they end up hating you for it. ;)
    The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it.
    Giant Anthem X