Tried to change the rear pads on my commuter last night and can’t get the pad retaining pin to unscrew. Front unscrewed fine, but the rear is stuck and the screw head appears to be made of cheese and is starting to chew up.

I’ve ordered a couple of allan headed pins so will have a spare one available.

I’m thinking hacksaw through the pin near the ‘security clip’ end, take the pads out then try using molegrips on the shaft to unscrew. Or just go straight to drilling out the stuck bolt and using a split pin instead of a bolt.

Tried tapping a screwdriver into the slot to free it last night but no joy.

Any other options?

Possibly try a torx key. They can, sometimes, undo a rounded allen key

Blowtorch?

Wouldnt take much heat yo expand the alluminium

Possibly try a torx key. They can, sometimes, undo a rounded allen key

Current screws are flat blade screwdriver heads

Penetrating oil and boiling water to heat up the caliper?

had this happen to me on an XTR caliper. Drilled the bolt out and replaced with a split pin. Zero issues

Penetrating oil and boiling water to heat up the caliper?

Sounds messy, might stain my garage floor 🙂 could take the bike into the house I suppose. 😕

Do the oil/boiling water but BEFORE you do that get an old allen key bit and epoxy it inside the screwhead..(giving it a good tap to make sure its as far in as it will go). (I did this with a bleed screw amongst other things)

Its a slot head screw so that isn’t an option unfortunately

Give the head of the pin a sharp tap with a hammer. This will break the chemical bond that has formed.

Put an elastic band over the head of the screwdriver and try again. Its a good bodge for rounded holes!.

Its not a rounded hole though, its a slot. like so 🙂

This has just happened to me only with an with an Allen headed pin. Was about to post this exact msg in order to find out what to do, how handy!!

Happy to help. You can go first, let me know how you get on 🙂

Can you just file two flat edges onto the screw head opposite each other then use mole grips…. i.e. if its like that picture…
(When you replace it use a hex or torx)

Once you free it the screwdriver will probably work.

Or file a slightly wider hole…

Tried the wider hole option, wasn’t successful. Filing flats might work but there’s not a lot of filing space even with the caliper removed, worth a go though.

I’d hacksaw the loops on the pads to get them out, then you have the full shaft of the pin to get molegrips onto, as tight as you can. Maybe try and get a second set on the head of the pin too ? Good squirt of GT85 into it first too.

Is it a 2-piece caliper? ( ?° ?? ?°)