"Chet" fired this volley in
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Hi Guys!
I run a 1/8 scale live steam locomotive.
While testing the vacuum brakes on my tender, I blew out the
diaphrams
that activate its brakes.
The original unit was used as a vacuum advance for old-time
carburetors and is now an endangered species.
Anybody have success making their own from scratch?
If so, would you be willing to share the process?
Thanks in advance,
Chet (engineer of ANCR Mogul #9401)


YES! I built my own cruise-control in the 1980s. I built a "sock"
type actuator. It's really simple.

Get an inner tube of the un-inflated diameter about what you want.
Find a piece of metal or plastic tubing into which it will fit
closely.
Find or fabricate a disk that will fit inside the inner tube when it
is doubled over inside itself.
Cement/fasten/clamp the inner tube to the disk. Then turn the whole
assembly inside-out, so the disk pulls the "inner" portion down inside
the "outer" portion.

Now slide the whole tube/disk affair inside your metal tubing, and
fold the free end of the inner tube over and around the butt-end of
the tube.

Seal it with a little adhesive between the outer surface of the metal
tube and the inner tube fold-over. Add over that a cap that fits
tight. Apply vacuum to the cap end.

You may also install a return spring inside, or rely upon an external
return spring.

Mine lasted eight years of daily interstate driving without a leak.

LLoyd