Anyone know anything about disc brakes?

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  • I've had success with a flathead bit and a set of molegrips holding it in place against the back of the pin then using a small adjustable to turn it all. When that's failed I've pulled the caliper in half, removed it using the body of the pin in a vice and then reassembling the caliper and refilling the system.

  • Spoke too soon pushed the pistons back on my hope rx and then got a small pop his and splatter of mineral oil from the lever . Now lost all pressure in the 8020 lever ! Is this a common lever fault . Left hand one btw.

  • @PhilDAS wins. In the bin, new one on its way. Not sure what that bolt is made from. Not sure it’s metal. 🧀

    Full saga:

    Rear brake is noisy.
    Take off wheel at home. Clean rotor. Decide to sand back pads a bit, as it’s been standing unused for a few months. Go to undo the retaining bolt - screwdriver churns up the thread on first go.
    Find a sharper screwdriver. Get the bolt inbound, but it seized up again.
    Spray WD40 and leave it to soak.
    Return. Try again. Screwdriver churns the thread up completely.
    Try the exposed other side with needle nose pliers. Snaps clean off.
    Things are starting to get annoying here.
    Get the drill out and find the stripped bolt bit. Whole head of bolt scrapes clean off.
    At this point I know it’s over.
    Drill into the bolt to remove it, still stuck.
    Remove calliper from bike, finding all my mineral oil has spilt into the bleed kit box. Problem for later.
    Saw a small incision onto bolt, try screwdriver again. Instantly strips.
    Cut through the bolt in the middle. Still seized
    Try undoing the torx nuts to disassemble the whole calliper. Spins around and nearly slices my finger off with the faced flat mount edge.
    Throw in bin, order new one from Sigma for £48.

    Worst thing is the brake was working fine, just loudly. Should have just left it. Off to France Monday, hoping Sigma’s next day truly is next day 🤞

  • They're all shit, every bike I see with said pad axle gets it removed and threads given a touch of anti seize, or if it's already fucked then either mentioned and ignored until later or fixed with more swearing.

  • Anyone got a lead on:

    105/Ultegra rear callipers in stock
    Shimano brake fluid


    Ideally in a physical shop in London, have seen there’s a few online options but would rather buy from a store.

  • I think I've got some 105 calipers in the workshop, defo GRX, although not London based so would still need posting. Shimano fluid is basically impossible to find still I think, you'll have to make do with something else.

  • Whereabouts are you? I’m in Ipswich

  • Manchester. DM me Monday and I'll see what's knocking about.

  • New pads in.

    I reckon this is too much lever throw - needs a bleed or more fluid? What do you lot reckon?

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  • Cute hands... ;)

  • French manicure too.

  • Whatever floats your boat. I don't remember anyone else every referring to my claws as "cute".
    Maybe you're getting confused given the angles.

  • Probably need new pads soon, Ultegra calipers, any point looking beyond swapping like for like with L05A-RF resin pads? SwissStop stuff? Will be used year round so just wondering if other pads might be better in wet conditions?

  • K05S if you don't need the fins and want to save some money.

  • Is there a decent disc brake mount facing tool that is significantly cheaper than the Park one that costs a five hundred quid?

    Both my bikes that have flat mounts are both carbon and both seem to have the same issue of excess paint/material left that makes it near impossible to set without any rub.

    There’s a tiny bit of paint that’s creating a high spot. I’m tempted to try shave it down a fraction with a Stanley blade, but I’m also a bit too pedantic to not use the correct tool for the job…

    Google isn’t showing any tools other than the pricey Park ones. Is there something else?

  • my brother in christ - just head to your LBS who probably have the park tools one

  • of course lbs is an option. But I have my own wee workshop in my garage thats fairly well equipped and as such I haven't used a lbs to do any work on my bikes for about 15 years.
    I'd happily buy a tool if theres another option other than £500 for the park one.

  • Is there something else?

    There's this for making individual spot faces more or less orthogonal to the fixing screw axis, you'll want a straight edge and some feeler gauges to get both faces in more or less the same plane.

    Obviously in a precision engineering situation you'd never use a threaded hole as a reference, but I bet it would get you close enough.

  • Try a blade, file or sandpaper if it's just paint, or go to a shop, ring ahead because a lot of places won't do it enough to warrant buying the tool which is why you shouldn't buy it either. Maybe cyclo or VAR do a cheaper one but it's still going to be more than getting someone else to do it on probably more bikes than you'll ever need it for.

  • Maybe cyclo or VAR do a cheaper one

    LOL at VAR being cheaper, theirs is more like £900. Cyclo is about £200, there's a popular Chinesium one called Super B for about the same

  • I didn't check, some of their stuff is good value at trade, whoops.

  • Thanks all. Obviously even two hundred odd quid on a tool that I might not even use again in my lifetime would be mental…

    I used a fresh Stanley blade and shaved the paint down in teeny tiny increments and it’s worked a treat, completely rub free now.

  • completely rub free now.

    It's been a while for me too.

  • I've got a GRX400 caliper that appears to be leaking from the bleed nipple. It's as snug as I can get it - is there an easy fix before I just warranty a new caliper?

    Spare bleed nipples are available (Y8CL98050), could it have failed?

  • could it have failed?

    It could, but it's most likely just the O ring Y8B511001. Probably best to get the kit just in case. If you're unlucky, the damage is in the seat and it's new caliper time.

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Anyone know anything about disc brakes?

Posted by Avatar for Sanddancer @Sanddancer