I’m trying to replace my rear mech which requires taking out 3 2.5mm screws. One came undone ok, the remaining two are stuck fast and I’ve now stripped the threads. Any tips on getting these out?

Do you mean the three teeny screws that attach the mech hanger to the frame?

Yep those ones

Is it the threads on the screw that are stripped or the head itself (from the tool slipping and chewing up the head)?

If the threads are stripped I hope you haven’t stripped the frame threads.

A pic of what you’re dealing with would be useful.

If the heads of the screws are rounded off and not accepting a hex/allen key then you could try a T15 torx bit tapped into the head to see if that will grip and remove the machine screw.

One came undone ok, the remaining two are stuck fast and I’ve now stripped the threads. Any tips on getting these out?

If the remaining two are stuck fast (not moving) then i can’t see how the threads in the mech hanger could be stripped?.

When changing rear mechs the dropout does not need to be removed, you use a 5mm hex to remove the mech from the mech hanger

A pic would help to pinpoint what you mean

Sorry, it’s the screw heads I’ve rounded off:

Top right screw is the one I can remove

cut a small crosshead into them using a dremel, then use a small flat head screw driver and a hammer and try tapping them around and out.

Why are you removing the dropout if you are just replacing the mech? That part stays on the frame unless it’s damaged.

The hanger is bent. I’m replacing that. Missed a word in my first post – sorry!

The heads are flush with the frame, so a dremel probably wouldn’t work. Would something like this be suitable: http://www.amazon.co.uk/Toolzone-Piece-Damaged-Remover-storage-x/dp/B009R1G3M2

Just drill the bolts with a 2.5mm bit

Don’t attempt to drill it out or try a screw extractor – it’ll end in tears, If it was my frame i would squeeze the dropout in a vice to lessen the tension in the screw then tap a suitably sized 1/4″ drive torx bit into the rounded off head and carefully apply torque to the bit – if that didn’t work i’d select a fine point centre punch and carefully tap it around the edge of the countersunk screw head with a small hammer in the direction of removal, if that didn’t work I’d secure the dropout under a pillar drill and enlarge the hex hole to a depth that i could tap in a larger torx bit along with a diamond filling/gripping compound to ensure a good contact.

You prob don’t have such tools/compounds so take it easy and rather than drilling out i’d take it to a reputable bike shop.

Thank you Soma

Drill heads off screws mech hanger will pull off then small set of mole grips to undo the screws as they will now be loose with a bit of luck did this on my old 224.

A bit late here, but a splash of PlusGas and leave overnight might help, if you haven’t already.

Buy two cheap Allen keys that fit and some Araldite. Glue the keys into each bolt, leaving overnight. Undo them the next day…….maybe.

Also a dab of heat? either heatgun the area or hold a soldering iron to the bolts for a few seconds – careful of your paint etc. – or and not if you’re just skooshed it in plusgas..