Disc pad pin stuck

chrisǃ Posts: 67
edited February 2019 in Workshop

So the times come to change my disc brake pads. The only issue is that the pad retaining bolt is stuck! They're Ultegra 8000 calipers and the bolt has a slotted head but is now pretty chewed up from trying to un do it!
Has anyone had this issue and sorted it?



  • proto
    proto Posts: 1,483
    My neighbour had the same problem on a Shimano caliper on his Canyon bike. He’d tried everything, ended up destroying the head.
    He removed the caliper from the frame, and I drilled through the core of the pin until it collapsed and I could get it out. I tapped the thread to clean it up, can’t remember if it was M3 or M4, but was a standard pitch, so easy to do. He got a new pin from somewhere. Caliper was saved.
  • frisbee
    frisbee Posts: 691
    My back one started to chew up the first time I tried to remove the pads, from memory I dug out a screw driver that fitted more snugly, gave it a gentle tap and tightened it slightly to break the corrosion.
  • rafletcher
    rafletcher Posts: 1,235
    And refit them with copaslip or similar anti-seize compound.
  • I had the same problem with the same caliper / pin. The material is really soft.

    I removed the caliper from the frame, and with pliers, mole grips and lots of swearing, finally got the knackered pin out.

    I replaced with these, they're slightly longer than needed, but the allen key head is much much better.

    https://www.wiggle.co.uk/shimano-br-m78 ... snap-ring/
  • timothyw
    timothyw Posts: 2,482
    If you do completely destroy the head/threading getting it out, I seem to recall that you can use a split pin to retain them instead (and indeed this comes as standard for a few shimano brake calipers).
  • Thanks for the replies! Looks like I'm going to have some fun getting this damn pin out this weekend!
  • david7m
    david7m Posts: 636
    Can you grab it with long nose panel grips between the pads on the smooth bit?
    You may only get one chance, make sure you've got it tight:)
  • Tyresome
    Tyresome Posts: 113
    Get some 40% Ammonia solution, and dose the calliper with it, then just heave with some mole grips until the pin comes out.
  • dabber
    dabber Posts: 1,926
    rafletcher wrote:
    And refit them with copaslip or similar anti-seize compound.

    A useful reminder to go check mine. I had the front one out a couple of weeks ago, no problem but must check the back.
    On the subject of copaslip (which I've previously used on my motorbike.... I guess only the very smallest amount in case of contamination on the pads/disc.
    “You may think that; I couldn’t possibly comment!”

    Wilier Cento Uno SR/Wilier Mortirolo/Specialized Roubaix Comp/Kona Hei Hei/Calibre Bossnut
  • Well after a little while and a lot of swearing we ended up drilling it out. The metal pin is just so soft! Even when you get some decent grip on it the pin just snaps. Ended up just drilling it out and using a split pin. A right pain in the arse but at least it's sorted now.
    Changed the pads on my Sram Red disc bike at the same time, done and dusted in 5 minutes!