Conley Silent Shutter piston service

[Fragomeni]

I have an uncommon item that I need to service. A Conley Silent Shutter. It works via a similar piston mechanism as a Packard shutter powered by a bulb. Everything works but the piston has a little more resistance than it should. The air pressure from the bulb is barely able to open the shutter and the suction is not able to close it. I’m able to get the tip of my pinky finger inside the inner edge of the piston interior and noticed that it feels a little waxy.

I haven’t serviced one of these before so am hoping for a little wisdom from those who may have seen one of these before or have serviced similar types of air powered shutter pistons. Am I right to assume that the interior of the piston should be clean and smooth? I can see that or even slightly oiled, but not waxy. That tells me there was oil that has gotten a bit gummed up. If thats correct, what would be the best protocol for cleaning it? Any help finding the right path would be appreciated. Thank you.

[Jim C.]

The red rubber hose looks crispy to me, it might be leaking from a crack somewhere on the hose causing pressure loss
I'd check that first. Especially near the nipple at the bottom of the piston.

The pneumatic piston isn't that complicated, yes it should be clean and smooth inside the bore of the cylinder and dry,
the piston should be as well, it's a loose slip fit brass on brass. Without seeing in the cylinder bore better it looks like there is a
pivot joint on the piston, remove the cylinder from the board and tilt it slightly to remove or pull straight down.
Clean the bore of the cylinder with lighter fluid ( naptha ) or isopropyl. On Packard shutters I have, I've polished the piston and the bore
with some metal polish, cleaned, then applied some teflon spray followed by a light buff after the spray dries.

[jnantz]

Hi Jim
If one doesn't have teflon spray could one use graphite dust ? that works like a charm with old deGroff pistons ...
John

[Fragomeni]

The red rubber hose looks crispy to me, it might be leaking from a crack somewhere on the hose causing pressure loss
I'd check that first. Especially near the nipple at the bottom of the piston.

The pneumatic piston isn't that complicated, yes it should be clean and smooth inside the bore of the cylinder and dry,
the piston should be as well, it's a loose slip fit brass on brass. Without seeing in the cylinder bore better it looks like there is a
pivot joint on the piston, remove the cylinder from the board and tilt it slightly to remove or pull straight down.
Clean the bore of the cylinder with lighter fluid ( naptha ) or isopropyl. On Packard shutters I have, I've polished the piston and the bore
with some metal polish, cleaned, then applied some teflon spray followed by a light buff after the spray dries.

Hi Jim,
Thanks very much for this. Very clearly explained and great info. And yes, the hose is a bit crispy. I hadn't considered that it may be losing pressure along the length of the hose-- great observation there. I'll hook up another hose and see how that improves things but will also use your advice to clean the piston surfaces if that doesn't solve it adequately. Thanks very much!

[Jim C.]

Hi John,
Powdered graphite would work too, I prefer the spray, the particles in the spray seems finer, both are messy.
JimC