Viewing 26 posts - 1 through 26 (of 26 total)
  • HELP! Drilling out a pad axle
  • Premier Icon trailwagger
    Free Member

    So I have managed to turn the head of the pad axle screw into jelly and there is no stock of new calipers until July next year.
    To avoid having a bike i cannot ride for six months i am going to try and bodge it by drilling out the ceazed jelly screw and replacing with a split pin.
    Question is, how best to drill it out? Slightly bigger drill bit that the bolt? Smaller and build up? how do you drill it out in the centre without damaging the small amount of caliper body around the bolt?

    Premier Icon weeksy
    Full Member

    What caliper ? Maybe someone can let you borrow one ?

    Premier Icon thepurist
    Full Member

    Can you cut the axle enough to get the pads out then have a go at it gripping the remaining stub of the axle bolt?

    Premier Icon trailwagger
    Free Member

    What caliper ? Maybe someone can let you borrow one ?

    105.

    Can you cut the axle enough to get the pads out then have a go at it gripping the remaining stub of the axle bolt?

    Not managed to grip it enough to loosen it from the head end or the opposite end so I am not hopeful of being able to do it from the middle.

    Premier Icon servo
    Free Member

    I had this with my Shimano road calipers with the bolt with the useless slot rather than the hex. The slot just broke off. I did drill it out and it doesn’t look pretty, but has been working with a split pin for about 3 years without a problem. Got a new Canyon bike with the same slot bolts and just put a MTB hex one in place as the hex heads are way better.

    Sorry, can’t remember how I actually drilled it out but remember it was a bit tricky. I am a bit ham fisted but I did it in the end.

    Premier Icon Greybeard
    Full Member

    What materials? I’m guessing the caliper will be alloy and the bolt stainless, so the drill will try to wander off into the softer material. A pillar drill will be much less liable to that than hand held. The bolt will probably go through a clear hole in the near side of the caliper, and only screw into the far side, so maybe attack from that side.

    I would look on eBay for a caliper.

    Premier Icon benman
    Free Member

    Those screws are terrible. I’ve had it twice now. First time we cut the screen in half between the pads, and the two halves unscrewed quite easily. 2nd time the thread had corroded in place, and we had to Dremel it out with tiny drill bits.
    All my road calipers now have hex head steel screws, which come with the MTB calipers.

    Premier Icon thols2
    Free Member

    I’m not familiar with your caliper, but if it’s like the one’s I know, you should be able to drill or grind the head off the retaining pin. That should relieve any tension on it and it might just unscrew without tools. If it doesn’t, if you can split the caliper in half, that should leave you enough sticking out to put into a vise and unscrew.

    Your chances of drilling the retaining pin out without wrecking the caliper are pretty much zero – the drill will just veer off into the softer aluminium rather than cutting the steel.

    Cutting or grinding the pads out might also help. You might be able to then cut the pin in the middle and grip it with pliers to unscrew it.

    Premier Icon Murray
    Full Member

    You could try heat – a soldering iron or a fine blowtorch e.g. a cooking one. Differential expansion should break the corrosion then you may be able to get it to turn by grabbing the pin.

    Premier Icon thols2
    Free Member

    You could try heat – a soldering iron or a fine blowtorch e.g. a cooking one.

    You’re liable to blow boiling hot brake fluid all over the place if you apply a blowtorch to the caliper.

    Premier Icon Murray
    Full Member

    You’re liable to blow boiling hot brake fluid all over the place if you apply a blowtorch to the caliper.

    Good point – I was assuming that the OP would remove the caliper to work on it, hence the hose would be removed. I was also assuming that the heat would be applied to the screw not the caliper (hence the soldering iron) but I should have been clearer.

    Premier Icon crossed
    Full Member

    I had this with my Ultegra caliper.
    You could try cutting the pin in the centre, removing the pads then try to unscrew the remaining seized bit of the pin with some vice grips. I tried that but the remaining part of the pin just broke off.

    To drill the pin out I knocked of the remaining part of the screw head so it was relatively flush with the caliper.
    Mark the centre of the remaining piece of the pin with a centre punch so the drill bit doesn’t slip then use some decent quality sharp drill bits (I used these https://www.screwfix.com/p/erbauer-straight-shank-hss-drill-bits-25-piece-set/2726v)

    Start small, I think I started with something like a 2mm bit. once that’s through then go up a size. I think I went up as far as 3mm or 3.5mm The other side of the caliper will also need the hole enlarged as it won’t take a decent size split pin otherwise.

    Premier Icon Murray
    Full Member

    If you’re going to drill it use a centre drill to start it

    Premier Icon andrewh
    Free Member

    The bolt will probably go through a clear hole in the near side of the caliper, and only screw into the far side, so maybe attack from that side.

    The end where the head is is usually the end with the thread. If your other caliper is the same kind take that out and check

    Premier Icon benman
    Free Member

    To drill the pin out I knocked of the remaining part of the screw head so it was relatively flush with the caliper.
    Mark the centre of the remaining piece of the pin with a centre punch so the drill bit doesn’t slip then use some decent quality sharp drill bits

    Exactly what I did. The screws are really soft to drill out, they aren’t steel.

    And the thread is definitely at the head end.

    Premier Icon bigyan
    Free Member

    Shimano road pads pins are made of aluminium (or cheese), they are commonly seized, rounded out or snapped regularly on bikes that come in for service.

    If you can use a drill they are easy to drill out, you can do it without damaging the threads in the caliper. The Shimano split pins that come with some pads work perfectly without having to drill out the caliper over size.

    I use a carbide burr to create a pocket (then centre punch) to start the drill in rather than trying to start it in a mangled slot. If the head is snapped off flush the just centre punch and drill.

    That said I have seen absolutely mangled calipers where customers have had a go, just depends on your ability/experience.

    Its only a very short threaded section which is why it can be done by hand.

    Premier Icon footflaps
    Full Member

    So I have managed to turn the head of the pad axle screw into jelly and there is no stock of new calipers until July next year.

    I bought a GRX calliper off Ebay as I couldn’t get a 105/600/DA one till 2023 apparently…

    Premier Icon PeterPoddy
    Free Member

    I’ve done a few of these. Not read the whole thread but the process is this

    1 Be aware this can happen. When it looks even slightly seized, stop before you ruin the slot! Wheel out, bike/calliper on the floor and supported on wood from behind. Find a well fitting flat blade screwdriver, and a hammer. With the rear of the CALLIPER supported on wood pop the screwdriver in the slot and hit it nice and hard a few times. This often breaks the corrosive bond and you can then press down hard enough whilst it’s still on the floor to remove the pin SLOWLY!! Might need a few more clouts. This works more often than not
    2 If it’s properly stuck you have nothing to loose but luckily (Ultegra especially) the pins are very soft. The head can be snapped off with pliers and then the pin gently drilled out. Don’t worry too much about the threads in the calliper, you’re not going to use them anyway and you’re on damage limitation anyway! Replace with a split pin
    3 Everyone else, right now, go and take those shitty pins out and either put a tiny dab of anti seize on them or bin them and pop a split pin in.

    I think I’ve done 6 in about the last 3 months…..

    Premier Icon pdw
    Free Member

    As others have said, they’re not actually that hard to drill out, and if you’re switching to split pin you don’t need to worry about taking out a bit of the caliper thread.

    Don’t do what I did which is successfully drill through the middle of the bolt and then try to get it out with a bolt extractor. It did come out quite cleanly, but only after cracking the eye of the caliper.

    Premier Icon pedlad
    Full Member

    Can anyone post a source for buying split pins (have ultegra road brakes but hope mtb so no split pins to swap in).?

    Premier Icon jkomo
    Full Member

    I managed to drill one out, smaller drill and managed to fold in the thread of the screw. A bit of thread was damaged but it still worked.
    I used a mtb pin to replace.

    Premier Icon bikerevivesheffield
    Full Member

    @pedlad Noah And Theo 10pcs Shimano compatible Disc Brake Pads Retaining Split Cotter Pins https://www.amazon.co.uk/dp/B017DDAHB8/ref=cm_sw_r_apan_glt_fabc_KDRAYS3CX3KKG8HXQ0KC

    Premier Icon slowoldman
    Full Member

    Let me get back to you once I’ve got this bloody mudguard bolt out of the fork crown.

    Premier Icon Speshpaul
    Full Member

    I’ve got a pair of ultegra direct mount calipers spare. They are a bit scabby due to the paint lifting, but the retaining bolts are out:-) £40 posted if that’s any use to you

    Premier Icon PJM1974
    Free Member

    Same problem here – this numpty rounded the pad retaining bolt in his Hope caliper during the last pad change.

    I’m thinking that I might see if I can tap a reverse thread into the bolt and extract it with a bolt or something?

    Premier Icon andrewh
    Free Member

    Can anyone post a source for buying split pins (have ultegra road brakes but hope mtb so no split pins to swap in).?

    I’ve got a big box of them, loads of sizes
    If you are anywhere near Galashiels you are welcome to pop round and try a few until you find some which fit and take a couple. PM me

Viewing 26 posts - 1 through 26 (of 26 total)

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