On Fri, 29 Apr 2005 22:09:11 GMT, Bruce L. Bergman
wrote:

On Fri, 29 Apr 2005 12:30:06 -0700, Larry Jaques
wrote:
On Fri, 29 Apr 2005 04:28:24 -0700, the inscrutable "Jon Danniken"
spake:

That was last week; this weekend I get to try and remove frozen bleeder
screws from my disc brake calipers; oh lucky me!

Got any R-12? (Totally non PC, and proud of it.) Freeze the screw,
heat the caliper body, and turn with a brake line wrench or 6-pt
socket.

Yeah, but at the price of R-12 nowadays you don't want to waste a
drop of it - and the price is only going to go in ^one^ ^direction^.
Use something cheaper, more benign and easier to get like CO2, R-22 or
R-134 for making with the freezing.

Try rocking or tapping the screw in both directions to break it
loose using a box wrench and a small hammer - mass quantities of force
applied on that little bitty bleeder screw are going to have bad
results, persuasion is called for.

-- Bruce --
Generally to get out a stuck bleeder I heat the tip of the bleeder to
red hot quickly with the torch, then smack it on the head lightly with
a small hammer. You don't want to put enough heat into it on an
aluminum caliper to affect the threads in the caliper, but that's
pretty hard to do given the thermal mass of the caliper and the fact
that the oxide layer makes a pretty good insulator. The heat swells
the screw, starting to fracture the oxide layer - and the smack with
the hammer does the rest. Shocking with a shot of ice-water instead of
the hammer also often works - if you NEED to salvage the bleeder screw
and can't risk flattening the tit on the end with a hammer.