[TheForge] Krause/Nazel type air hammer

[Jeff Harding]

Larry;

   If this is true, then replacing the cups would not "rebuild" the
cylinder.  I have rebuilt many that were only dripping a little
without even honing the cylinder by simply cleaning and replacing the
cups.  Also, if it's the piston fit alone that holds the pressure then
honing the cylinder would trash that fit and it would not work with
the same piston.  I only honed when the cylinder was scarred enough to
damage the cups and have done rebuilds on irreplaceable cylinders that
provided braking, but still dripped a little and would bleed off if
you kept your foot on it long enough.
    It's the cups and the directional fit that hold the pressure, put
the cups in backwards and it won't brake and won't return to position
when you let off of the pedal.   Over hone it and you are done too,
the fit won't hold pressure.  There is barely enough room to stuff
that cup into the bore along with the piston.

       We may be talking of very different vintage brake parts here,
I went from rebuilding out of necessity because that is how it was
done to buying rebuilt cylinders because it was cheaper than spending
my time.  I've not had but one cylinder fail since I was much younger
and I just had that one replaced by my mechanic,  this was after I
could no longer lean over a fender for any length of time.  Those days
are coming to an end, I've been rebuilt too...

   You are absolutely right about the end caps and such, they are to
keep dirt out, but not the seals on the piston.  Again... your
experience may well be "modern" compared to mine. I have rebuilt
cylinders as recently as 15 years ago in this manner, but they were
from "antique" cars.

   However,  the heat issue is definitely a factor, pliable parts
aren't going to hold up to heat at all.

   Jeff   ><>



> The pressure is held in the brake cylinders by the little pistons,
the
> rubber parts are to keep out the dust.
> L Brown
>