Front derailleur anchor bolt threading

[Gingi]

Hi. I am unable to tighten the anchor bolt on my front derailleur
(Shimano Ultegra, FD-6503). It seems that the threading of either the
bolt or the anchor bolt housing is worn down (so turning the Allen
wrench doesn't do anything). I can't really tell whether it's the bolt
or the housing, but I tried two other bolts (from my bottle cage) and
got the same result.

My question: if it's the housing that is worn down, is my front
derailleur hosed and I need to replace it? Or is there some way to
reconstitute the threading?

Any help is appreciated.
Shiran

 

[Leo Lichtman]

"Gingi" WROTE: (Clip) Or is there some way to
> reconstitute the threading? Any help is appreciated.
^^^^^^^^^^^^^^
The female threads are part of the deraileur clamp? Can you use a longer
bolt and put on a nut?

Or: Loc-tite makes a thread restoration product that replaces the missing
metal. Not good for highly stressed applications, but it ought to work fine
for this. You spray a release agent on the bolt threads. You coat the
threads, male and female, with a two-part epoxy resin mix, and screw the
thing together. After it cures, you can unscrew the bolt, and it will leave
usable threads in the hole.

 

[Qui si parla Campagnolo]

On Jun 27, 6:34 pm, Gingi <[email protected]> wrote:
> Hi. I am unable to tighten the anchor bolt on my front derailleur
> (Shimano Ultegra, FD-6503). It seems that the threading of either the
> bolt or the anchor bolt housing is worn down (so turning the Allen
> wrench doesn't do anything). I can't really tell whether it's the bolt
> or the housing, but I tried two other bolts (from my bottle cage) and
> got the same result.
>
> My question: if it's the housing that is worn down, is my front
> derailleur hosed and I need to replace it? Or is there some way to
> reconstitute the threading?
>
> Any help is appreciated.
> Shiran


If ya do need a new FD, don't get a 6603 or DA 7703 as they are made
for a 53(2)/39 and the length of the inside cage will hit the 42t on
your crank when in the big ring(thanks shimano)..I think the 5603 will
work as it is made for a 50/40....

 

[* * Chas]

"Leo Lichtman" <[email protected]> wrote in message
news:[email protected]...
>
> "Gingi" WROTE: (Clip) Or is there some way to
> > reconstitute the threading? Any help is appreciated.
> ^^^^^^^^^^^^^^
> The female threads are part of the deraileur clamp? Can you use a
longer
> bolt and put on a nut?
>
> Or: Loc-tite makes a thread restoration product that replaces the
missing
> metal. Not good for highly stressed applications, but it ought to work
fine
> for this. You spray a release agent on the bolt threads. You coat the
> threads, male and female, with a two-part epoxy resin mix, and screw the
> thing together. After it cures, you can unscrew the bolt, and it will
leave
> usable threads in the hole.
>
>

Front derailleur clamp bolts and nuts need to be pretty tight to keep the
derailleur from rotating on the seat post so in that sense they may be too
highly stressed for the Loc-tite product.

I've had to file the flats on FD clamps more than a few times to get a
tighter fit.

Chas.