Rivnut bottle mount seized

Simon Brooke said:

in message <[email hidden]>, Paul - [censored]

(') said:

Mark came up with the following;:

Quoted message said:

I have an aluminium-framed Cannondale bike with a bolt seized into
the rivnut bottle mount, which itself is loose in the frame. I can't
grab the rivnut securely enough with needle-nosed pliers to be able
to loosen the now-mangled bolt. Argh! I only undid the bloody bolt a
couple of weeks ago and now it's seized!

Ideas?!

Drill, angle grinder, welder ... I guess a lot depends on how much of
the rivnut is available.

Dear man, this is a Cannondale, show some respect!

To start at the beginning: have you now knackered the rivnut so much
it has to come out anyway? If not, try degreasing the area thoroughly
and epoxying the rivnut in place, giving the epoxy plenty of time to
cure, and then /gently/ try the bolt again. This isn't particularly
likely to work but it's worth a try.

It's not completely knackered -- I gave up on trying to hold it in place
and posted my original message before I fully buggered it up. However,
it's mildly chewed around the edges so a new one would look nice and
might stay seated for longer.

Quoted message said:

Failing that I would be trying the angle grinder, but /very/
carefully, trying to take the top off the rivnut without touching the
tube. A drill isn't going to work as the rivnut will just rotate in
the hole. You REALLY do not want to touch the tube with an angle
grinder!

Yes, I can well imagine. My father's into making models and has a
variety of miniature grinder tools which might do the job in a more
controllable manner than a 11,000rpm Bosch monster. Luckily the rivnut
is loose enough to insert a sheet of something hard between the flange
and downtube to offer some protection.

My next worry is whether I'll be able to retrieve the rivnut from the
inside of the downtube, presumably via an opening to the BB shell or
headtube. I'll take out the BB (needs replacing anyway) and have a look
for a suitable hole.

In replies to other posts: I do know that you can tighten rivnut with a
nut, bolt and washer; I was trying to remove the bottle mount bolt in
order to do so. It worked like a charm on the seat tube mount.

Cheers,

Mark

Alexander Rice said:

Come to think of it if you've got some threads projecting out of the
rivnut already you might be able to tighten the rivnut then remove the
bolt afterwards.

Presumably if the bolt is still in the Rivnut as in the OP's case, you
can take the head off the bolt, thread the nut on from the top and then
hold the body of the bolt with mole grips or a slot cut in the end while
you tighten up the rivnut with the nut.

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

in message <[email hidden]>, Mark

(') said:

My next worry is whether I'll be able to retrieve the rivnut from the
inside of the downtube, presumably via an opening to the BB shell or
headtube.

You will. This won't be a problem at all. It will just fall down into the
bottom bracket shell all by itself, once you've taken the top off it.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

The Conservative Party now has the support of a smaller proportion of
the electorate in Scotland than Sinn Fein have in Northern Ireland.

Tony Raven said:

Alexander Rice said:

Come to think of it if you've got some threads projecting out of the
rivnut already you might be able to tighten the rivnut then remove
the bolt afterwards.

Presumably if the bolt is still in the Rivnut as in the OP's case, you
can take the head off the bolt, thread the nut on from the top and
then hold the body of the bolt with mole grips or a slot cut in the
end while you tighten up the rivnut with the nut.

There's not enough of the thread showing to be able to do this. I think
I'm going to take the bolt head off and grind/file away the lip so the
old rivnut drops into the tube then replace it with a new one.

Cheers all,

Mark