Removing mangled limit screw?

[MADB]

Ok this was bit down to me and bit bit down the how ever owned the mech in the first place. It was seized which is probably why it was in a bad way, but I have got it to turn now, just don't quite know how to attack it now? Any idears?

 

[KermitGKona88]

Re:

Use a decent screwdriver and be very gentle

 

[Bullpup]

Re:

It looks to me as though there is some threadlock on the screw?

Try removing it with brake cleaner or similar?

 

[Raging_Bulls]

I assume you're talking about the bottom one in the mech itself? I'd like to know too.

I have one that is fubar-ed and had to file down the fin on the inside of the cage to set the "H" limit just right it for my Scott.
Unless someone knows a fix for a completely flattened head, I'll probably never be able to use that rear mech (an M735) again on any other bike.

 

[MADB]

You got it, a little annoyed by this one.

Current thinking is to see if a can get the dremel into the bottom on the screw to either square it off so I can use needle nose or cut out a bit for a small flat screw driver. Screw it out from the bottom as much as I can, them reaccess.

With a bit of luck the head of the screw will be more accessible.

A daft idea?

 

[aunderhi]

What about cleaning the grease/dirt/crap off of it and using JB Weld or two part epoxy to glue a tiny nut to the top of the screw, then take it off with a wrench? Maybe even plumber's epoxy? (superglue doesn't work afaik)

 

[Raging_Bulls]

Pretty daft. I at some point put the mech in a vice, took a sharpened flathead screwdriver and hammered a new 1mm deep groove into the head ... which promptly gave way the second I tried turning the screw.

 

[MADB]

Drill it out then? or put it back on the bike it works fine on and put the ruff looking one back on this one ( the Avanti).

I should just find a new mech..........

 

[hamster]

I find that drilling a hole, then hitting reverse and pushing hard with a cordless drill often works and unwinds mangled bolts.

 

[marc two tone]

Re:

As an alternative, i once drilled the other end of the screw,reducing it's length, the end that touches the mech parts that determine the travel. Are they nobbles, tangs, sticky out bits? you know what i mean!

This got me what i needed. It put the mech(front) where i wanted it. As i couldn't get down to granny ring. So it's worth being careful not to remove to much of the screw. Assuming getting a drill bit in there is possible.

I know how seriously seized these screws can be. Above example is to get things happening, not so much a permanent solution as future adjust-ability is compromised.